DTC Troubleshooting

DTC P1128: MAP Sensor Signal Lower Than Expected

NOTE:
- Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
- Before starting this troubleshooting check for poor connections or blockage at the air intake duct.

1. Turn the ignition switch ON (II).
2. Compare the value of the MAP SENSOR and the 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 10.

NO - Go to step 3.

3. Note the value of MAP SENSOR in the DATA LIST with the HDS.
4. Start the engine, and let it idle.
5. 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 6.

NO - Go to step 10.

6. Clear the DTC with the HDS.
7. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle.
8. Test-drive under these conditions:
- Engine speed above 1,750 rpm
- Transmission in D position
- REL TP SENSOR above 22 °
- Drive 5 seconds or more

9. Monitor the OBD STATUS for DTC P1128 in the DTCs MENU with the HDS.

Does the screen indicate FAILED?

YES - Go to step 10.

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 7 and recheck.

10. Turn the ignition switch OFF.
11. Replace the MAP sensor.
12. Turn the ignition switch ON (II).
13. Reset the PCM with the HDS.
14. Do the PCM idle learn procedure.
15. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle for 10 seconds.
16. Test-drive under these conditions:
- Engine speed above 1,750 rpm
- Transmission in D position
- REL TP SENSOR above 22 deg
- Drive 5 seconds or more

17. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P1128 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 18.

18. Monitor the OBD STATUS for DTC P1128 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 17, go to the indicated DTCs 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 15.