ENGINE CONTROLS - TESTS W/CODES - 3.1L ENGINE -1997 Chevrolet Lumina
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DTC P0300-P0308 - ENGINE MISFIRE DETECTED
NOTE:
DTC P0300 is set when the ECM recognizes a general misfire in the
engine. If the ECM determines the cylinder causing the misfire it will set a
specific DTC P0301-P0308, to indicate the number of the cylinder causing the misfire. If a DTC P0301-P0308 is retrieved, use this procedure to
diagnose the misfire condition in the indicated cylinder.
Circuit Description
Misfire is detected using Camshaft Position (CMP) and Crankshaft Position (CKP) sensors. When PCM senses CKP deceleration not associated with normal engine speed reduction, CMP is used to determine
misfiring cylinder. PCM determines misfires on each cylinder and evaluates a random misfire and set DTC.
Conditions required to set code are:
? No VSS DTCs set.
? No CKP, CMP, ECT, MAF, MAP or TP sensor DTCs set. ? Engine speed 450-5800 RPM.
? System voltage 9-16 volts.
? ECT 21-248°F (-6 to 120°C). ? Throttle angle steady.
? PCM detects crankshaft RPM variation, indicating a misfire which could cause catalytic convertor damage or high emissions.
Diagnostic Procedures
Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK. See the BASIC TESTING
3.1L article. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
If DTC P1200 is also set, go to DTC P1200
Start engine and allow it to idle. Using scan tool, read and record FREEZE FRAME data. Operate vehicle within conditions noted in FREEZE FRAME data. Using scan tool, read MISFIRE CUR #
display for each cylinder. If MISFIRE CUR # is increasing (indicating a misfire currently occurring) for any cylinder, go to next step. If MISFIRE CUR # is not increasing, go to
DIAGNOSTIC AIDS.
If MISFIRE HIST # displays a very large number for more than one cylinder, go to next step. If MISFIRE HIST # does not display a very large number for more than one cylinder, go to step 14).
Check vacuum hoses for splits, kinks, or improper connections. If a problem is found, repair as necessary. After repairs, go to step 30). If no problem is found, go to next step.
Check PCV valve for improper installation or damaged "O" rings. If a problem is found, repair as necessary. After repairs, go to step 30). If no problem is found, go to next step.
Check throttle body inlet screen for blockage or foreign objects which may partially block airflow sample through MAF sensor. If a problem is found, repair as necessary. After repairs, go to step
-
1.
. If DTC P1200 is not set, go to next step.
2. 3.
4.
5.
6.
7.
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ENGINE CONTROLS - TESTS W/CODES - 3.1L ENGINE -1997 Chevrolet Lumina
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30). If no problem is found, go to next step.
Check fuel pressure. See FUEL SYSTEM in the SYSTEM/COMPONENT TESTS article. If a problem is found, repair as necessary. After repairs, go to step 30). If no problem is found, go to
next step.
Check for fuel contamination. If fuel is contaminated, repair condition causing contamination. After repairs, go to step 30). If fuel is okay, go to next step.
10. Check PCM power and sensor grounds for clean and tight connection, and for proper location. If a problem is found, repair as necessary. After repairs, go to step 30). If no problem is found, go to
next step.
Disconnect MAF sensor harness connector. Operate vehicle within conditions noted in FREEZE FRAME data. Using scan tool, read MISFIRE CUR # display for each cylinder. If MISFIRE CUR
# is increasing (indicating a misfire currently occurring) for any cylinder, go to next step. If MISFIRE CUR # is not increasing, go to step 27).
Check intake manifold, injector "O" rings, EGR adapter, EGR valve, and EGR feed pipes for vacuum leaks. If a problem is found, repair as necessary. After repairs, go to step 30). If no
problem is found, go to next step.
13. Remove EGR valve and inspect valve, seat and passages for damage. Inspect valve pintle to ensure it is not sticking partially open. If a problem is found, repair as necessary. After repairs, go
to step 30). If no problem is found, go to next step.
14. Check for proper injector operation. Install Adaptor Harness (J 34730-380 & J 34730-385) to 10- pin fuel injector harness connector. Attempt to start engine. If all LEDs for cylinders No. 1-6
flash, go to next step. If not all LEDs for cylinders No. 1-6 flash, go to step 16).
15. Check for proper injector operation. See INJECTOR CIRCUIT TEST under FUEL SYSTEM DIAGNOSIS in the BASIC TESTING - 3.1L article. If a problem is found, repair as necessary.
After repairs, go to step 30). If no problem is found, go to step 17).
Check affected injector circuit(s) from PCM for open, shorted to ground, or for poor connection. Repair as necessary. After repairs, go to step 30). If circuits are okay, go to step 29).
Check ignition wire(s) associated with cylinder(s) that is misfiring. If a problem is found, repair as necessary. After repairs, go to step 30). If no problem is found, go to next step.
Install a spark tester on spark plug wire at spark plug end for cylinder indicating most severe misfire. Connect a jumper wire between engine ground and companion cylinder spark plug wire at
spark plug end. Companion cylinders are 1/4, 2/5, and 3/6. Crank engine and check for crisp, Blue spark at tester. Repeat procedure for each affected cylinder. If spark is okay on all cylinders, go to
step 23). If spark is not okay on any cylinder, go to next step.
Remove ignition coil(s) associated with misfiring cylinder(s). Check ignition coils for cracks or carbon tracking. If a problem is found, replace damaged coil(s). After repairs, go to step 30). If no
problem is found, go to next step.
20. Check ignition coil secondary resistance. If resistance is not 5000-8000 ohms, replace ignition coil. After replacing ignition coil, go to step 30). If resistance is as specified, go to next step.
Remove ignition wire(s) associated with misfiring cylinder(s). Check ignition wire(s) boot for carbon tracking or damaged insulation. If a problem is found, replace faulty ignition wire(s). After
repairs, go to step 30). If no problem is found, go to next step.
Check resistance of ignition wire(s) associated with misfiring cylinder(s). If resistance is greater than 30,000 ohms, replace ignition wire(s). After replacing wire(s), go to step 30). If resistance is
not greater than 30,000 ohms, go to step 28).
Remove spark plug
8.
9.
11.
12.
16.
17.
18.
19.
21.
22.
(s) associated with misfirin
g
c
y
linder(s). Check spark plu
g
s fo
r
excessive
23.
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ENGINE CONTROLS - TESTS W/CODES - 3.1L ENGINE -1997 Chevrolet Lumina
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fouling. If spark plugs are excessively fouled, diagnose and repair mechanical engine problem. If spark plugs are not excessively fouled, go to next step.
Check spark plug insulation for cracks, carbon tracking or other damage. If a problem is found, replace faulty spark plug(s). After replacing spark plug(s), go to step 30). If no problem is found,
go to next step.
Diagnose mechanical engine problem. If a problem is found, repair as necessary. After repairs, go to step 30). If no problem is found, go to next step.
Check for transmission DTCs. See the TRANSMISSION SERVICING article. If a problem is found, repair as necessary. After repairs, go to step 30). If no problem is found, see
DIAGNOSTIC AIDS.
Replace MAF sensor. After replacing sensor, go to step 30).
Replace ignition control module. After replacing module, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, read and record FREEZE FRAME data. Clear DTCs. Start engine and allow it to idle. Operate vehicle within conditions noted in FREEZE FRAME data. Using scan tool, read
MISFIRE CUR # display for each cylinder. If MISFIRE CUR # is increasing (indicating a misfire currently occurring) for any cylinder, return to step 2). If MISFIRE CUR # is not increasing,
repair is complete.
24.
25.
26.
27. 28.
29.
30.
Diagnostic Aids
Tips Click a link to view tip
Tip: DTC P0300
Check secondary ignition wires. Check for damaged or faulty ignition coil. Substitute a known-good ignition coil. Check system grounds. Check MAF sensor, air induction system, fuel pressure, injectors,
and EGR valve.
Extended idle periods or short trip driving could leave deposits on HO2S. Deposits could cause HO2S to respond slowly, affecting fuel control and causing misfire at idle.
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ENGINE CONTROLS - TESTS W/CODES - 3.1L ENGINE -1997 Chevrolet Lumina
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DTC P0336 - CKP SENSOR CIRCUIT
NOTE:
For circuit reference, see the appropriate WIRING DIAGRAMS article. For
connector and terminal identification, see CONNECTOR
IDENTIFICATION.
Circuit Description
Ignition Control Module (ICM) produces 24X reference signal. ICM calculates 24X reference signal by filtering Crankshaft Position (CKP) sensor 24X pulses when engine is running and CKP pulses are also
being received. PCM uses this information to calculate engine speed and CKP at engine speeds less than 1200 RPM. PCM compares number of 24X reference pulses to 3X reference pulses and Camshaft
Position (CMP) pulses. If PCM receives incorrect number of pulses, DTC P0336 will set.
Conditions required to set DTC are:
? Engine running and PCM receiving 3X reference pulses.
? Ratio of 24X reference pulses to 3X reference pulses received by PCM does not equal 8. ? Ratio of 3X reference pulses to CMP pulses received by PCM equals 6.
? Listed conditions occur for 30 seconds.
Diagnostic Procedures
Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK. See the BASIC TESTING
3.1L article. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
Attempt to start engine. If engine starts and runs, go to next step. If engine does not start and run, see ENGINE DOES NOT START in the BASIC TESTING - 3.1L article.
Using scan tool, clear DTC P0336. Start engine and allow it to idle for
DTC P0336 resets, go to next step. If DTC does not reset, go to DIAGNOSTIC AIDS.
Disconnect CMP sensor connector. Using a DVOM, check voltage at Camshaft Position (CMP) sensor and Crankshaft Position (CKP) sensor feed circuit. If DVOM reads battery voltage, go to
step 8). If DVOM does not read close to battery voltage, go to next step.
Turn ignition off. Disconnect PCM harness connector. Turn ignition, with engine off. Using a fused jumper wire connected to battery voltage, connect jumper wire to sensor feed circuit. Check
for voltage at reference signal circuit. If DVOM reads battery voltage, go to step 14). If DVOM does not read close to battery voltage, go to next step.
Check 24X CKP sensor and CMP sensor feed circuits for short to ground. If a problem is found, repair as necessary. After repairs, go to step 15). If no problem is found, see DIAGNOSTIC
AIDS.
7. Check connections at PCM and replace terminals as necessary. After repairs, go to step 15). If terminals are okay, go to next step.
Check reference signal circuit connections at CKP sensor. Replace terminals as necessary. After repairs, go to step 15). If terminals are okay, go to next step.
Check reference signal circuit for open or short to ground. Repai
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1.
2.
3.
One minute. Read DTCs. If
4.
5.
6.
8.
R
as necessary. After repairs, go
9.
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to step 15). If circuit is okay, go to next step.
Disconnect 24X reference circuit to CKP and CMP sensors. Using DVOM, check continuity between CMP sensor harness reference low to CKP harness reference low circuit. Check
continuity between CKP harness reference low circuit and PCM. If DVOM reads continuity (zero ohms) on both tests, go to step 12). If continuity does not exists, go to next step.
Check for open in circuits, or faulty connections at PCM or sensors. Repair as necessary. After repairs, go to step 15).
Turn ignition off. Disconnect 24X CKP sensor connector. Turn ignition on. Using a test light connected to battery voltage, probe reference low circuit at harness connector. If test light
illuminates, go to next step. If test light does not illuminate, go to step 14). Replace 24X CKP sensor. After replacing sensor, go to step 14).
Check connections to PCM. If connections are okay, replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Read and record FAIL RECORDS data for DTC P0336. Operate vehicle within conditions noted in FAIL RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0336
FAILED THIS IGN, return to step 2). If scan tool does not display DTC P0336 FAILED THIS IGN, repair is complete.
10.
11.
12.
13. 14.
15.
Diagnostic Aids
Check for incorrect harness routing near secondary ignition components, ignition coil arcing to wiring harness or ICM. Check ignition coils for cracks, carbon tracking or other signs of damage. Check for
secondary ignition wire(s) arcing to wiring harness.
Check for faulty connections or damaged harness. Observe a voltmeter connected to 24X CKP sensor reference circuit at PCM harness connector while moving all related harness and connectors. A change
in voltage indicates fault location.
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ENGINE CONTROLS - TESTS W/CODES - 3.1L ENGINE -1997 Chevrolet Lumina
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DTC P0341 - CAMSHAFT POSITION SENSOR CIRCUIT
NOTE:
For circuit reference, see the appropriate WIRING DIAGRAMS article. For
connector and terminal identification, see CONNECTOR
IDENTIFICATION.
Circuit Description
DTC P0341 will set if Camshaft Position (CMP) sensor pulses are not in proper ratio to 24X and 3X pulses.
Conditions required to set DTC are:
? Engine running and PCM receiving 3X reference pulses.
? Ratio of 3X reference pulses to CMP pulses received by PCM does not equal 6.
? Ratio of 24X reference pulses to 3X reference pulses received by PCM does not equal 8. ? Conditions present for 30 seconds.
Diagnostic Procedures
Tips Click a link to view tip
Tip: P0341 code runs ok but has hard fault. Has trans range code also.
Tech1
Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK. See the BASIC TESTING
3.1L article. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
Using scan tool, read and record FAIL RECORDS data for DTC P0341. Operate vehicle within conditions noted in FAIL RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool
displays DTC P0341 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0341 FAILED THIS IGN, see DIAGNOSTIC AIDS.
3. Turn ignition off. Disconnect PCM connectors. Connect a test light between battery voltage and PCM harness connector sensor feed circuit. If test light illuminates, leave test light connected and
go to next step. If test light does not illuminate, go to step 6).
Disconnect CMP sensor connector. If test light illuminates, go to next step. If test light does not illuminate, go to step 11).
Check for short to ground in CMP and 24X CKP sensors feed
as necessary. After repairs, go to step 14). If no problem is found, see DIAGNOSTIC AIDS.
Connect a fused jumper wire between PCM harness connector sensor feed circuit and battery voltage. Using a DVOM, check voltage between engine ground and PCM harness connector CMP
signal circuit. If voltage is near battery voltage, leave fused jumper wire connected and go to next step. If voltage is not near battery voltage, go to step 8).
Check voltage between engine ground and PCM harness connector sensor ground circuit. If voltage is near battery voltage, go to step 12). If voltage is not near battery voltage, go to step 10).
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1.
2.
4.
5.
Circuit. If a problem is found, repair
6.
7.
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8.
Check for open CMP sensor feed circuit. If circuit is open, repair as necessary. After repairs, go to step 14). If circuit is okay, go to next step.
Check for open or short in CMP sensor signal circuit. If a problem is found, repair as necessary. After repairs, go to step 14). If no problem is found, go to step 11).
Check for open CMP sensor ground circuit. If open is found, repair as necessary. After repairs, go to step 14). If no open is found, go to next step.
Replace CMP sensor. After replacing sensor, go to step 14).
Check for faulty connections at PCM. If a faulty connection is found, repair as necessary. After repairs, go to step 14). If connections are okay, go to next step.
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Read and record FAIL RECORDS data for DTC P0336. Operate vehicle within conditions noted in FAIL RECORDS data. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0336
FAILED THIS IGN, return to step 2). If scan tool does not display DTC P0336 FAILED THIS IGN, repair is complete.
9.
10.
11. 12.
13.
14.
Diagnostic Aids
Check for incorrect harness routing near secondary ignition components, ignition coil arcing to wiring harness or ICM. Check ignition coils for cracks, carbon tracking or other signs of damage. Check for
secondary ignition wire(s) arcing to wiring harness.
Check for faulty connections or damaged harness. Observe a voltmeter connected to CMP sensor signal circuit at PCM harness connector while moving all related harness and connectors. A change in voltage
indicates fault location.
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DTC P1652 - FAN 2 RELAY CONTROL CIRCUIT
NOTE:
For circuit reference, see the appropriate WIRING DIAGRAMS article. For
connector and terminal identification, see CONNECTOR
IDENTIFICATION.
Circuit Description
Output Driver Modules (ODMs) are used by Powertrain Control Module (PCM) to turn on current driven devices that are needed to control various engine and transaxle functions. Each ODM can control
up to 7 separate outputs by grounding the device that PCM is commanding on. ODMs can diagnose each output circuit individually. DTC P1652 indicates an improper voltage level has been detected on fan 2
relay driver (control) circuit.
Diagnostic Procedures
Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK. See the BASIC TESTING 3.1L article. After performing OBD system check, go to next step.
Turn ignition off. Disconnect PCM connector. Turn ignition on. Using DVOM, check voltage between ground and fan 2 relay driver circuit terminal at PCM connector. If battery voltage is
present, go to next step. If battery voltage is not present, go to step 6).
Set ammeter to 10-amp range. Check current between ground and fan 2 relay driver circuit terminal at PCM connector. Monitor reading for a minimum of 2 minutes. If current is 0.1-1.5
amps, go to step 11). If current is not 0.1-1.5 amps, go to next step.
Turn ignition off. Disconnect fan 2 relay connector. Turn ignition on, with engine off. Using DVOM, check voltage between ground and fan 2 relay driver circuit at fan 2 relay harness
connector. If voltage is zero volts, go to step 10). If voltage is not zero volts, go to next step. Locate and repair short to voltage in fan 2 relay driver circuit. After repairs, go to step 16).
Remove and inspect fuse for fan 2 relay. If fuse is blown, go to next step. If fuse is okay, go to step 8).
Locate and repair short to ground in ignition feed circuit for fan 2 relay. Replace fuse. After repairs, go to step 16).
Disconnect fan 2 relay. Turn ignition on. Measure voltage between ground and ignition feed circuit terminal at fan 2 relay harness connector. If battery voltage is present, go to next step. If
battery voltage is not present, go to step 13).
Check for an open or short to ground in fan 2 relay driver circuit. Repair as necessary. After repairs, go to step 16). If circuit is okay, go to next step.
Check fan 2 relay driver circuit and ignition feed circuit for poor terminal connection at fan 2 relay connector and at PCM connector. Repair as necessary. After repairs, go to step 16). If
connections are okay, go to step 14).
Turn ignition off. Reconnect PCM connector. Disconnect fan 2 relay connector. Turn ignition on. Connect a test light between fan 2 relay driver circuit and ignition feed circuit terminals at fan 2
relay harness connector. Using scan tool, select OUTPUTS TEST function and cycle fan 2 relay on and off. If test light flashes, see DIAGNOSTIC AIDS. If test light does not flash, go to next
step.
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2.
3.
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5. 6.
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8.
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10.
11.
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12.
Check fan 2 relay driver circuit for poor terminal connection at PCM. Repair as necessary. After repairs, go to step 16). If connection is okay, go to step 15).
Locate and repair open in ignition feed circuit to fan 2 relay. After repairs, go to step 16). Replace fan 2 relay. After replacing relay, go to step 16).
Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
Using scan tool, select CLEAR INFO or CLEAR DTCS function to clear DTCs. Turn ignition on, with engine off. Using scan tool, review FREEZE FRAME data and note parameters. Start engine
and operate vehicle within conditions required for setting this DTC, and as close to conditions recorded in FREEZE FRAME as possible. Monitor SPECIFIC DTC info for DTC P1652 until
DTC P1652 test runs. If scan tool indicates FAILED THIS IGN, repeat step 2). If scan tool does not indicate FAILED THIS IGN, repair is complete.
13. 14. 15.
16.
Diagnostic Aids
Disconnect and inspect PCM connector. Inspect for damaged pins, corrosion and loose wires. An intermittent problem can be caused by a poor connection, rubbed-through wire insulation or broken wire
inside insulation. Reviewing FAIL RECORDS vehicle mileage since diagnostic test last failed may help determine how often condition that caused DTC to be set occurs.
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Friday, January 27th, 2012 AT 3:32 AM
