DTC Troubleshooting
DTC Troubleshooting: P1129
DTC P1129: MAP Sensor Signal Higher Than Expected
NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information. Initial Inspection and Diagnostic Overview
1. Check for vacuum or air leaks in these parts:
- PCV valve
- PCV hose
- EVAP canister purge valve
- Throttle body
- Intake air duct (air flow tube)
- Intake manifold
- Brake booster
- Brake booster hose
- Turbocharger
- Intake air duct (turbocharger inlet tube and pipe)
- Intake air duct (turbocharger outlet pipe)
- Charge air cooler
- Intake air duct (charge air cooler inlet hose)
- Intake air duct (charge air cooler outlet tube)
- Turbocharger bypass control solenoid valve
- Pressure regulator
Are there any vacuum or air leaks?
YES - Repair or replace parts with vacuum or air leaks, then go to step 9.
NO - Go to step 2.
2. Turn the ignition switch to ON (II).
3. Compare the value of the MAP SENSOR and TURBOCHARGER BOOST SENSOR in the DATA LIST with the HDS.
Does the value differ more than 26.7 kPa (7.9 in.Hg, 200 mmHg)?
YES - Go to step 11.
NO - Go to step 4.
4. Note the value of MAP SENSOR in the DATA LIST with the HDS.
5. Start the engine, and let it idle.
6. Check the MAP SENSOR in the DATA LIST with the HDS.
Does the MAP SENSOR change 0.67 kPa (0.2 in.Hg, 5 mmHg) or more?
YES - Go to step 7.
NO - Go to step 11.
7. Clear the DTC with the HDS.
8. Start the engine. Hold the engine speed at 3000 rpm without load (in P or N) until the radiator fan comes on, then let it idle.
9. Test-drive under these conditions:
- Engine speed above 1,750 rpm
- Transmission in D
- REL TP SENSOR above 22 deg
- Drive 5 seconds or more
10. Monitor the OBD STATUS for DTC P1129 in the DTCs MENU with the HDS.
Does the screen indicate FAILED?
YES - Go to step 1.
NO - If the screen indicates PASSED, intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the MAP sensor and the PCM. If the screen indicates NOT COMPLETED, go to step 5 and recheck.
11. Turn the ignition switch to LOCK (0).
12. Replace the MAP sensor. Service and Repair
13. Turn the ignition switch to ON (II).
14. Reset the PCM with the HDS.
15. Do the PCM idle learn procedure. PCM Idle Learn Procedure
16. Start the engine. Hold the engine speed at 3,000 rpm without load (in P or N) until the radiator fan comes on, then let it idle.
17. Test-drive under these conditions:
- Engine speed above 1,750 rpm
- Transmission in D
- REL TP SENSOR above 22 deg
- Drive 5 seconds or more
18. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1129 indicated?
YES - Check for poor connections or loose terminals at the MAP sensor and the PCM, then go to step 1.
NO - Go to step 19.
19. Monitor the OBD STATUS for DTC P1129 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES - Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in step 18, go to the indicated DTC's troubleshooting.
NO - If the screen indicates FAILED, check for poor connections or loose terminals at the MAP sensor and the PCM, then go to step 1. If the screen indicates NOT COMPLETED, go to step 16.