P1128

DTC Troubleshooting: P1128, P1128

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 Initial Inspection and Diagnostic Overview.
- Before starting this troubleshooting, check for poor connections or a blockage at the intake air duct.

1. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

2. Check the MAP SENSOR in the DATA LIST with the HDS.

Is less than 54.1 kPa (16.0 inHg, 406 mmHg) or 1.61 V held for more than 5 seconds?

YES -

Go to step 7.

NO -

Go to step 3.

3. Clear the DTC with the HDS.

4. 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.

5. Test-drive under these conditions:

- Engine coolant temperature (ECT SENSOR 1) above 158 °F (70 °C)
- Engine speed about 1,200 rpm or more
- A/T in D, M/T in 3rd
- Vehicle speed about 25 mph (40 km/h) or more under half throttle

6. Monitor the OBD STATUS for DTC P1128 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 4 and recheck.

7. Turn the ignition switch to LOCK (0), or press the engine start/stop button to select the OFF mode.

8. Replace the MAP sensor Service and Repair.

9. Turn the ignition switch to ON (II), or press the engine start/stop button to select the ON mode.

10. Reset the ECM/PCM with the HDS.

11. Do the ECM/PCM idle learn procedure ECM/PCM Idle Learn Procedure.

12. 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.

13. Test-drive under these conditions:

- Engine coolant temperature (ECT SENSOR 1) above 158 °F (70 °C)
- Engine speed about 1,200 rpm or more
- A/T in D, M/T in 3rd
- Vehicle speed about 25 mph (40 km/h) or more under half throttle

14. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P1128 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.

15. 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 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.