DTC P1129: MAP Sensor Signal Higher Than Expected
- Check for vacuum leaks in these parts:
- PCV valve
- PCV hose
- EVAP canister purge valve
- Throttle body
- Intake manifold
- Brake booster
- Brake booster hose
Are there any vacuum leaks?
YES -Repair or replace parts with vacuum leaks, then go to step 9.
NO -Go to step 2.
- Start the engine. Hold the engine speed at 3.000 rpm (min-1 ) without load (in Park or neutral) until the radiator fan comes on, then let it idle.
- Check the MAP SENSOR in the DATA LIST with the HDS.
Is more than 36.9 kPa (277 mmHg, 11.0 in.Hg) or 1.1 V held for more than for 5 seconds?
YES -Go to step 7.
NO -Go to step 4.
- Clear the DTC with the HDS.
- Test-drive under these conditions:
- Engine coolant temperature (ECT SENSOR 1) above 70°C (158°F)
- A/T in D position (M/T in 5th gear)
- Drive at a steady speed between 88-120 km/h (55-75 mph) for 10 seconds
- During the drive, decelerate (with the throttle fully closed) for at least 2 seconds
- Monitor the OBD STATUS for DTC P1129 in the DTCs MENU with the HDS.
Does the screen indicate FAILED?
YES -Go to step 7.
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 ECM/PCM. If the screen indicates NOT COMPLETED, go to step 5 and recheck.
- Turn the ignition switch OFF.
- Replace the MAP sensor (see MAF SENSOR/IAT SENSOR REPLACEMENT ).
- Turn the ignition switch ON (II).
- Reset the ECM/PCM with the HDS.
- Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ).
- Start the engine. Hold the engine speed at 3,000 rpm (min-1 ) without load (in Park or neutral) until the radiator fan comes on, then let it idle.
- Test-drive under these conditions:
- Engine coolant temperature (ECT SENSOR 1) above 70°C (158°F)
- A/T in D position (M/T in 5th gear)
- Drive at a steady speed between 88-120 km/h (55-75 mph) for 10 seconds
- During the drive, decelerate (with the throttle fully closed) for at least 2 seconds
- 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 ECM/PCM, then go to step 1.
NO -Go to step 15.
- 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 DTSs were indicated in step 14, 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 ECM/PCM, then go to step 1. If the screen indicates NOT COMPLETED, go to step 12.