Hi,
I see why you are questioning a vacuum leak or low fuel pressure. I'm not sure what was plugged off or how you checked for a leak, but take a look through this link and see if it is how you did it.
https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge
If you are certain that isn't the issue, here are the diagnostics for both codes you have. Take a look through them and let me know if it is something you feel comfortable doing.
H40 DTCS P0171, P0174, P1130, P1131, P1150, OR P1151: LEAN SYSTEM DTCS
Note:Do not clear the DTCs or reset the keep alive memory (KAM).
Fuel System and HO2S DTC Reference List:
- Bank 1 = DTC P0171 (lean)
- Bank 2 = DTC P0174 (lean)
- HO2S-11 = DTCs P1130 and P1131
- HO2S-21 = DTCs P1150 and P1151
- Access and record the ECT PID from the freeze frame data. The freeze frame data will be used to recreate the concern.
- Retrieve and record the self-test DTCs.
Are any DTCs present other than P0171, P0174, P1130, P1131, P1150, or P1151?
Yes
- DISREGARD the current diagnostic trouble code (DTC) at this time. GO to Section 4, Diagnostic Trouble Code (DTC) Charts See: A L L Diagnostic Trouble Codes ( DTC ) > Diagnostic Trouble Code Descriptions > Diagnostic Trouble Code (DTC) Charts and REPAIR the other DTCs.
No
- GO to H41
.
H41 CARRY OUT A VISUAL INSPECTION OF THE INTAKE AIR SYSTEM AND ALL VACUUM HOSES
- Check the intake air system for leaks, obstructions, and damage.
- Inspect the entire length of all the vacuum hoses for:
- proper connections.
- damage or cracks.
- damaged or cracked vacuum tees.
- Verify the integrity of the positive crankcase ventilation (PCV) system.
- Verify the proper PCV valve part number.
Is a concern present?
Yes
- GO to H44
.
No
- GO to H42
.
H42 CHECK FOR THE PRESENCE OF A VACUUM LEAK
Note:Fuel trim values at idle are more sensitive to a vacuum leak. The vacuum leak (unmetered air) represents a larger portion of the total air flow at idle than at part throttle.
Note:The barometric pressure (BARO) PID is not a recommended PID to monitor when diagnosing a vacuum leak. Barometric pressure is calculated during high engine load, when the vacuum leak represents a small portion of the total air flow.
Note:As an example, when calculating the total fuel correction in the following steps, if LONGFT1 = +13% and SHRTFT1 = +23%, the total fuel correction for bank 1 = +36%, also if LONGFT2 = +24% and SHRTFT2 = -3% the total fuel correction for bank 2 = +21%.
Note:If the freeze frame ECT PID is available, stabilize the engine at the temperature recorded by the freeze frame ECT PID. If the freeze frame ECT PID is not available, maintain the engine coolant temperature between 82°C - 101°C (180°F - 215°F) and the intake air temperature less than 46°C (115°F).
- Key on, engine running.
- Access and monitor the ECT or CHT, IAT, LONGFT1, SHRTFT1, LONGFT2 and SHRTFT2 PIDs.
- Allow the engine to stabilize at the temperature necessary to recreate the concern.
- Add and record the LONGFT PID value to the SHRTFT PID value for each bank, for a total fuel correction at idle.
- Increase the engine speed to 2500 rpm for 10 seconds.
- Record the LONGFT1, SHRTFT1, LONGFT2, and SHRTFT2 PID values.
- Add and record the LONGFT PID value to the SHRTFT PID value for each bank, for a total fuel correction at 2500 rpm.
Is the total fuel correction value change, between idle and 2500 rpm, less than 15 percent?
Yes
- No vacuum leak is present.
- GO to H47
.
No
- GO to H43
.
H43 LOCATE THE VACUUM LEAK
image
CAUTION: Do not clamp or pinch a hard plastic hose. Use a vacuum cap or equivalent to restrict the hose.
Note:Restricting the EVAP vapor hose while the EVAP emission canister is purging may shift the SHRTFT. Carry out a visual inspection as necessary.
Note:As an example, when monitoring for a decrease in the SHRTFT PIDs in the following steps, if SHRTFT1 is +15%, but when the hose is restricted SHRTFT1 decrease to -7%, the decrease in the SHRTFT PIDs = 22 percent.
- Locate the vacuum tees for the intake air and PCV systems.
- Access and monitor the SHRTFT1 and SHRTFT2 PIDs.
- Restrict the vacuum lines one at a time for 30 seconds. If a vacuum leak is present, the SHRTFT PID values will decrease as the hose is restricted.
Is the decrease in the SHRTFT PIDs greater than 15 percent when one of the vacuum hoses is restricted?
Yes
- GO to H44
.
No
- INSPECT the intake air system for a vacuum leak in the intake manifold or intake gaskets. REPAIR as necessary.
- For repair verification, GO to H44
.
H44 VACUUM LEAK REPAIR VERIFICATION
Note:If the freeze frame ECT PID is available, stabilize the engine at the temperature recorded by the freeze frame ECT PID. If the freeze frame ECT PID is not available, maintain the engine coolant temperature between 82°C - 101°C (180°F - 215°F) and the intake air temperature less than 46°C (115°F).
- Access and monitor the SHRTFT1 and SHRTFT2 PIDs.
- Allow the engine to stabilize at the temperature necessary to recreate the concern.
- Record the SHRTFT1 and SHRTFT2 PID values.
- Key off.
- Repair the vacuum leak.
- Key on, engine running.
- Allow the engine to stabilize at the temperature necessary to recreate the concern.
- Access and monitor the SHRTFT1 and SHRTFT2 PIDs.
- Compare the recorded SHRTFT PID values, prior to the vacuum leak repair, to the current SHRTFT PID values.
Is the decrease in the SHRTFT PIDs greater than 15 percent?
Yes
- Fault found.
- RESET the keep alive memory (KAM). REFER to Section 2, Resetting The Keep Alive Memory (KAM) See: Computers and Control Systems > Diagnostic Trouble Code Tests and Associated Procedures > Resetting The Keep Alive Memory (KAM).
No
- A vacuum leak is still present, GO to H43
.
H45 DTCs P1132 AND P1152: UPSTREAM HO2S NOT SWITCHING.
Note:It is necessary to address all Continuous Memory Ignition and Misfire DTCs, if received during Continuous Memory testing, before addressing any KOER HO2S DTCs.
DTC/HO2S Reference List:
- HO2S-11 = DTC P1132
- HO2S-21 = DTC P1152
- Check intake air system for leaks, obstructions and damage.
- Check air cleaner element, air cleaner housing for blockage.
- Verify integrity of the PCV system.
- Check for vacuum leaks.
Were any concerns found during inspection?
Yes
- REPAIR as necessary.
No
- GO to H47
.
H46 DTCs P0172 AND P0175: FUEL SYSTEM AT THE CORRECTED FUEL TRIM
Note:It is necessary to address all Continuous Memory Ignition and Misfire DTCs, if received during Continuous Memory testing, before addressing any Fuel Trim DTCs.
Fuel System DTC Reference List:
- Bank 1 = DTC P0172 (rich)
- Bank 2 = DTC P0175 (rich)
- Check intake air system for leaks, obstructions and damage.
- Check air cleaner element, air cleaner housing for blockage.
- Verify integrity of the PCV system.
- Check fuel delivery system and filter for restriction.
- Check for vacuum leaks.
Were any concerns found during inspection?
Yes
- REPAIR as necessary. COMPLETE KAM Reset.
No
- GO to H47
.
H47 PERFORM KOER SELF-TEST
- Disconnect fuel vapor hose from intake manifold and plug fitting at intake manifold.
- Start engine and run at 2000 rpm for 5 minutes and return to idle.
- Complete Key On Engine Running (KOER) Self-Test.
Are any HO2S DTCs P1127, P1128, P1129, P1131, P1132, P1151 or P1152 present?
Yes
- KEY OFF. If DTC P1127, P1128 or P1129 is present, GO to Section 4, Powertrain Diagnostic Trouble Code (DTC) Charts See: A L L Diagnostic Trouble Codes ( DTC ) > Diagnostic Trouble Code Descriptions > Diagnostic Trouble Code (DTC) Charts and REPAIR those DTCs first.
- DTCs (P1131, P1130) or (P1151, P1150):
- GO to H48
.
- DTCs (P1132, P1130) or (P1152, P1150):
- GO to H54
.
No
- KEY OFF.For Continuous Memory DTCs Only P1130, P1150, P0171, P0174, P0172 and P0175:
- GO to H57
.
- If DTC(s) P1132 and/or P1152 are no longer present, RECONNECT fuel vapor line.
- Vehicles experiencing KOER DTC 1131, 1132, 1151 or 1152:
REFER to Evaporative Emissions System for system leakage.
- All others without recurring DTCs:
- Unable to duplicate or identify fault at this time. GO to Z1 See: Computers and Control Systems > Diagnostic Trouble Code Tests and Associated Procedures > Z: Intermittent - Pinpoint Test
.
H48 HO2S CIRCUIT TEST (WITH LEAN DTCs)
- Disconnect the HO2S related to the DTC.
- Key on, engine off.
- Access the correct HO2S PID.
Note:If arcing occurs (indicating a short), remove jumper and GO to H52 (check fuse in the heater circuit).
- Jumper the HO2S SIG circuit to the VPWR circuit at the HO2S vehicle harness connector.
Is the reading 1.30 volts or greater?
Yes
- KEY OFF. CHECK SIG RTN circuit. GO to H49
.
No
- KEY OFF. GO to H51
.
H49 CHECK SIGNAL RETURN CIRCUIT FOR OPEN
- Measure resistance of HO2S SIG RTN circuit between the HO2S harness connector and the battery negative post.
Is the resistance reading less than 5.0 ohms?
Yes
- GO to H57
.
No
- GO to H50
.
H50 CHECK HO2S SIGNAL RETURN CIRCUIT FOR OPEN IN HARNESS
- Disconnect PCM.
- Measure resistance of HO2S SIG RTN circuit between the PCM harness connector pin and HO2S harness connector.
Is the resistance reading less than 5.0 ohms?
Yes
- REPLACE PCM. REFER to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) See: Computers and Control Systems > Programming and Relearning > Flash Electrically Eraseable Programmable Read Only Memory - Flash EEPROM.
No
- REPAIR open circuit.
Continued: See: Computers and Control Systems > Pinpoint Tests > H51 - H111
Let me know if this helps or if you have other questions.
Take care,
Joe
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Monday, October 19th, 2020 AT 6:06 PM
