ENGINE CONTROLS - TESTS W/CODES -1998 Lincoln Continental
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CIRCUIT TEST DD - FUEL RAIL PRESSURE (FRP) SENSOR
NOTE:
After each service or repair procedure has been completed, reconnect all
components. Clear DTCs and repeat QUICK TEST procedures to ensure
all EEC-V systems are working properly and DTCs are no longer present.
Diagnostic Aids
Perform this test when directed by QUICK TEST. This CIRCUIT TEST is intended to diagnose the following:
? FRP sensor.
? Wiring harness circuits (FRP Signal and SIG RTN). ? Powertrain Control Module (PCM).
Fig. 13: Identifying Fuel Rail Pressure (FRP) Sensor Circuits & Connector Terminals
FRP SENSOR VOLTAGE-TO-FUEL PRESSURE CONVERSION CHART Volts
4.5 3.9
3.4 2.8
2.2 1.6
1.1.5
Pressure (psi) 70
60 50
40 30
20 10 0
1) DTC P0192
This DTC indicates FRP voltage signal is less than self-test minimum. Possible causes for this fault are:
? FRP signal is shorted to SIG RTN or PWR GND. ? FRP circuit is open.
? Low fuel pressure. ? Faulty FRP sensor.
? Faulty PCM.
Ensure vehicle has fuel. Turn ignition on. Using scan tool, access FRP PID from PID/DATA monitor menu. If PID voltage is less than.2 volt, go to step 3). If PID voltage is.2 volt or more,
go to step 12).
NOTE:
A break in step numbering sequence occurs at this point. Procedure
skips from step 1) to step 3). No test procedures have been omitted.
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3) Generate Opposite Signal
Turn ignition off. Disconnect FRP sensor connector. Connect a jumper wire between FRP terminal and VREF terminal at FRP sensor wiring harness connector. If scan tool communication
problem is present, disconnect jumper wire and go to step 23). Using scan tool, select FRP V PID from PID/DATA monitor menu. If PID voltage is 4.6 volts or less, disconnect jumper wire and go
to next step. If PID voltage is more than 4.6 volts, replace FRP sensor.
4) Measure VREF Voltage
With FRP sensor disconnected, turn ignition on. Measure voltage between VREF terminal and SIG RTN terminal at FRP sensor wiring harness connector. If voltage is 4-6 volts, go to next step.
If voltage is not 4-6 volts, reconnect sensor and go to CIRCUIT TEST C.
5) Check FRP Circuit Resistance
Turn ignition off. Leave FRP sensor disconnected. Disconnect PCM 104-pin connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Install Breakout Box
(014-00950), leaving PCM disconnected. Measure resistance between FRP terminal at FRP sensor wiring harness connector and test pin No. 14 at breakout box. If resistance is less than 5 ohms, go
to next step. If resistance is 5 ohms or more, repair open in VPWR circuit.
6) Check FRP Circuit For Short To PWR GND Or SIG RTN
Measure resistance between test pin No. 14 and test pins No. 91 (SIG RTN), 24 and 103 (PWR GND) at breakout box. If any resistance reading is less 10,000 ohms or less, repair short circuit. If
all resistance readings are more than 10,000 ohms, replace PCM.
7) DTC P0193
This DTC indicates FRP voltage signal is more than self-test maximum. Possible causes for this fault are:
? FRP signal is shorted to VREF or PWR. ? High fuel pressure.
? Faulty FRP sensor. ? Faulty PCM.
Turn ignition on. Using scan tool, select FRP V sensor from PID/DATA monitor menu. If PID voltage is more than 4.8 volts, go to step 9). If PID voltage is not as specified, fault may be
intermittent. Go to step 14).
NOTE:
A break in step numbering sequence occurs at this point. Procedure skips from step 7) to step 9). No test procedures have been omitted.
9) DTC P0193: Generate Opposite Signal
Turn ignition off. Disconnect FRP sensor connector. Turn ignition on. Using scan tool, select FRP V PID from PID/DATA monitor menu. If scan tool communication problem is present, disconnect
jumper wire and go to step 23). If PID voltage is less than.2 volt, replace FRP sensor. If PID
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ENGINE CONTROLS - TESTS W/CODES -1998 Lincoln Continental
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voltage is.2 volt or more, go to step 11).
10) DTC P0190
Possible causes for this fault are:? VREF open circuit.
? VREF open is sensor.
Disconnect FRP sensor connector. Turn ignition on. Measure voltage between VREF and SIG RTN terminals at FRP sensor wiring harness connector. If voltage is 4-6 volts, go to step 12). If
voltage is 4-6 volts, go to next step.
11) Check For Open Circuit
Turn ignition off. Disconnect PCM 104-pin connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Install Breakout Box (014-00950), leaving PCM
disconnected. Measure resistance between test pin No. 14 and test pins No. 90 (VREF) and 91 (SIG RTN) at breakout box. If both resistance readings are less than 5 ohms, go to next step. If
any resistance reading is 5 ohms or more, repair open circuit.
12) Measure FRP Sensor Resistance
Measure resistance between FRP and SIG RTN sensor terminals. If resistance is not 30-40 k/ohms, replace FRP sensor. If resistance is 30-40 k/ohms, proceed as follows:
? If Continuous Memory DTC P0190 is present, go to step 14). ? If DTC P0192 is present, replace PCM.
? If DTC P0193 is present, go to next step.
13) Check FRP Circuit For Short To VREF Or VPWR
Disconnect PCM 104-pin connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure
resistance between test pin No. 14 and test pins No. 90 (VREF) and 71 (VPWR) at breakout box. If both resistance readings are more than 10,000 ohms, replace PCM. If any resistance reading is
10,000 ohms or less, repair short circuit.
14) Check For Intermittent Fault
Reconnect FRP sensor connector. Turn ignition on. Using scan tool, select FRP V PID from PID/DATA monitor menu. Observe PID voltage for fault while tapping on FRP sensor. Wiggle
and bend wiring harness and connector between sensor and PCM. Fault will be indicated by a sudden change in PID voltage. If fault is indicated, isolate and repair as necessary. If fault is not
indicated, symptom is intermittent and cannot be located at this time. Go to CIRCUIT TEST Z for additional test procedures.
15) Check Fuel Pressure - KOEO/KOER DTC P0191
DTC P0191 indicates the FRP sensor has exceeded the Self-Test Calibration limits and can only be retrieved during KOEO and KOER Self-Test. DTC P0191 (FRP) circuit malfunction low limit
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is 1.6 volts 138 kPa (20 psi) for gasoline vehicles, or 1.3 volts @ 586 kPa (70 psi) for natural gas and 3.9 volts at 413 kPa (60 psi) for gasoline vehicles, or 3.7 volts @ 724 kPa (130 psi) for natural
gas. Continuous DTC P1168 indicates the FRP sensor reading is too low. Continuous DTC P1169 indicates the FRP sensor reading is too high. DTC 1168 low limit is 551 kPa (80 psi). DTC 1169
high limit is 896 kPa (130 psi). Possible causes for this fault are:? High fuel pressure.
? Low fuel pressure.
? Excessive resistance in circuit. ? Faulty FRP sensor.
? Low or no fuel.
NOTE:
If DTC P0230 or P0231 is present, service these DTCs before
proceeding with this test.
Turn ignition on. Ensure vehicle has sufficient fuel. Turn ignition off. Release fuel pressure. Connect pressure gauge to Schrader valve. With engine running, check fuel pressure. If the
pressure reading within 138 kPa (20 psi) and 413 kPa (60 psi) for gasoline, or 552 kPa (80 psi) and 827 kPa (120 psi) for natural gas vehicles (NG), go to next step. If the pressure reading is not
within 138 kPa (20 psi) and 413 kPa (60 psi) for gasoline, or 552 kPa (80 psi) and 827 kPa (120 psi) for natural gas vehicles (NG), go to CIRCUIT TEST HC for gasoline or CIRCUIT TEST
HB for NG.
16) Check FRP PID Fuel Pressure
Turn ignition on. Using scan tool, select FRP PID from PID/DATA monitor menu. If PID psi reading is within 10 psi of fuel pressure gauge psi reading in step 15), go to step 18). If PID psi
reading is not within 10 psi, repeat QUICK TEST.
17) Check Fuel Rail Solenoid
Using scan tool, access OUTPUT TEST MODE. While observing fuel rail solenoid, cycle output on and off several times. If solenoid clicking can be heard or felt, exit output test mode and go to
next step. If no solenoid clicking can be heard or felt, go to step 21).
18) Measure VREF Voltage
Disconnect FRP sensor connector. Turn ignition on. Measure voltage between VREF terminal and SIG RTN terminal at FRP sensor wiring harness connector. If voltage is 4-6 volts, go to next step.
If voltage is not 4-6 volts, reconnect sensor and go to CIRCUIT TEST C.
19) Check FRP Circuit For Excessive Resistance
Turn ignition off. Disconnect PCM 104-pin connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary. Install Breakout Box (014-00950), leaving PCM
disconnected. Measure resistance between FRP terminal at FRP sensor wiring harness connector and test pin No. 14 at breakout box. Measure resistance between SIG RTN terminal at FRP sensor
wiring harness connector and test pin No. 91 (SIG RTN) at breakout box. Also, measure resistance between VREF terminal at FRP sensor wiring harness connector and test pin No. 90 at
breakout box. If all resistance readings are less than 5 ohms, go to next step. If any resistance
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reading is 5 ohms or more, repair circuit.
20) Monitor FRP Circuit With Scan Tool
Turn ignition on. Using scan tool, select FRP V PID from PID/DATA monitor menu. If PID voltage is less than.2 volt, replace FRP sensor. If PID voltage is not as specified, replace PCM.
21) Check Voltage At Fuel Rail Solenoid
Using scan tool, access OUTPUT TEST MODE and select ALL ON. Disconnect fuel rail solenoid connector. Measure voltage between VPWR circuit terminal at fuel rail solenoid wiring harness
connector and negative terminal. If voltage is more than 10.5 volts, go to next step. If voltage is 10.5 volts or less, repair open in VPWR circuit.
NOTE:
When in output test mode, voltage measurement must be made
within 7 seconds of activating test mode.
22) Check Ground Circuit
Using scan tool, access OUTPUT TEST MODE and select ALL ON. Measure voltage between VPWR and ground circuit terminals at fuel rail solenoid wiring harness connector and negative
terminal. If voltage is more than 10.5 volts, replace fuel rail solenoid. If voltage is 10.5 volts or less, repair open circuit.
23) Check VREF Voltage To FRP Sensor
Disconnect FRP sensor connector. Turn ignition on. Measure voltage between VREF and SIG RTN circuit terminals at FRP sensor wiring harness connector. If voltage is 4-6 volts, go to next
step. If voltage is not 4-6 volts, VREF is out of range. Go to CIRCUIT TEST C.
24) Check For Shorted FRP Signal
Turn ignition off. Disconnect scan tool Data Link Connector (DLC). Disconnect PCM 104-pin connector. Inspect connector for loose, damaged or corroded terminals. Repair as necessary.
Install Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between test pin No. 14 and test pins No. 90, 91, 24 and 103 at breakout box. If all resistance readings are more
than 10,000 ohms, replace PCM. If any resistance reading is 10,000 ohms or less, repair short circuit.
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See image for pinout.
Image (Click to make bigger)
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