DTC P1129: MAP Sensor Signal Higher than Expected
- Check for vacuum leaks at 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 the part(s) with vacuum leaks, then go to step 9.
NO - Go to step 2.
- Start the engine. Hold the engine speed at 3, 000 RPM without load (A/T in P or N, M/T in neutral) until the radiator fan comes on, then let it idle.
- Check the MAP SENSOR in the DATA LIST with the HDS.
Is there more than 36.9 kPa (11.0 inHg, 277 mmHg), or 1.14 V held for more than 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 158°F (70°C)
- Engine speed between 1, 200 and 5, 900 RPM
- A/T in D, or M/T in 5th
- Drive at a steady speed between 55- 75 mph (88-120 km/h) for 10 seconds, then decelerate (with the throttle fully closed) for 5 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 to LOCK (0), or press the engine start/stop button to select the OFF mode.
- Replace the MAP sensor .
- Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.
- 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 without load (A/T in P or IM, M/T in neutral) until the radiator fan comes on, then let it idle.
- Test-drive under these conditions:
- Engine coolant temperature (ECT SENSOR 1) above 158°F (70°C)
- Engine speed between 1, 200 and 5, 900 RPM
- A/T in D, or M/T in 5th
- Drive at a steady speed between 55- 75 mph (88- 120 km/h) for 10 seconds, then decelerate (with the throttle fully closed) for 5 seconds
- Check for Pending or Confirmed 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 Pending or Confirmed DTCs 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.