DTC P1128: MAP Sensor Signal Lower Than Expected

NOTE: 

• Before you troubleshoot, review the general troubleshooting information - Refer to: How to Troubleshoot the Fuel and Emissions SystemsHow to Troubleshoot the CVT System(CVT System) .
• Before you troubleshoot, check for poor connections or a blockage at the intake air duct.

DTC (PGM-FI)

• 1. MAP sensor performance check:

  - 1. Turn the vehicle to the ON mode.

  - 2. Check the parameter(s) below with the HDS.

  Signal	Threshold		Current conditions
  	Values	Unit	Values	Unit
  MAP SENSOR	Less than 54.1	kPa

  Do the current conditions match the threshold for 5 seconds or more?

  YES 

  Replace the MAP sensor .

  NO 

  Go to step 2.

• 2. Problem verification:

  - 1. Clear the DTC with the HDS.

  - 2. 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.

  - 3. Test-drive under these conditions:

  • Engine coolant temperature (ECT SENSOR 1) above 158°F (70°C)
  • Engine speed at 1, 400 rpm or more
  • Transmission in D
  • Vehicle speed accelerated to 15 mph (24 km/h) or more under half throttle

  Signal	Current conditions
  	Values	Unit
  ECT SENSOR 1
  ENGINE SPEED
  VEHICLE SPEED

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

  DTC Description	OBD STATUS
  P1128 MAP Sensor Signal Lower Than Expected

  Does the HDS indicate FAILED?

  YES 

  The failure is duplicated. Replace the MAP sensor .

  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 freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot. If the HDS indicates NOT COMPLETED, go to step 2-2 and recheck.