P1128

DTC Troubleshooting: 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 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 (in P or N) 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)
- Transmission in D
- Engine speed about 1,200 rpm or more
- Drive at a steady speed about 15 mph (24 km/h) or more (under half throttle) for 2 seconds or more

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

Does the HDS indicate FAILED?

YES -

Go to step 7.

NO -

If the HDS 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 HDS 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 PCM with the HDS.

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

12. 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.

13. Test-drive under these conditions:

- Engine coolant temperature (ECT SENSOR 1) above 158 °F (70 °C)
- Transmission in D
- Engine speed about 1,200 rpm or more
- Drive at a steady speed about 15 mph (24 km/h) or more (under half throttle) for 2 seconds or more

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 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 HDS 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 HDS indicates FAILED, check for poor connections or loose terminals at the MAP sensor and the PCM, then go to step 1. If the HDS indicates NOT COMPLETED, go to step 12.