DTC P1128: MAP Sensor Signal Lower Than Expected
- Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).
- Also, before you troubleshoot, check for poor connections or a blockage at the intake air duct.
- Inspect the air cleaner element (see AIR CLEANER ELEMENT INSPECTION/REPLACEMENT ).
- Turn the ignition switch ON (II).
- Check the MAP SENSOR in the DATA LIST with the HDS.
Is there less than 54.1 kPa (16.0 in.Hg, 406 mmHg) or 1.61 V held for more than 5 seconds?
YES -Go to step 8.
NO -Go to step 4.
- Clear the DTC with the HDS.
- 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.
- Test-drive under these conditions:
- Engine coolant temperature (ECT SENSOR 1) above 158 °F (70 °C)
- Engine speed between 1,400 and 6,500 rpm
- A/T in D position (M/T in 3rd gear)
- Vehicle speed accelerated from 16 mph (25 km/h) to 31 mph (50 km/h) under half throttle
- Monitor the OBD STATUS for DTC P1128 in the DTCs MENU with the HDS.
Does the screen indicate FAILED?
YES -Go to step 8.
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 MAP 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 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 158 °F (70 °C)
- Engine speed between 1,400 and 6,500 rpm
- A/T in D position (M/T in 3rd gear)
- Vehicle speed accelerated from 16 mph (25 km/h) to 31 mph (50 km/h) under half throttle
- 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 ECM/PCM, then go to step 1.
NO -Go to step 16.
- 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 15, 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 ECM/PCM, then go to step 1. If the screen indicates NOT COMPLETED, go to step 14.