DTC P1128
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 .
- Before you begin, check for poor connections or a blockage at the intake air duct.
| DTC Description | Confirmed DTC | Pending DTC | Freeze Frame |
|---|---|---|---|
| P1128 MAP Sensor Signal Lower Than Expected |
DTC (PGM-FI)
- MAP sensor performance check
-1. Turn the vehicle to the ON mode.
-2. Check the parameter(s) below with the HDS.
Signal Malfunction Threshold Current conditions Values Unit Values Unit MAP SENSOR Less than 54.1 kPa Less than 1.61 V Did the value maintain the malfunction threshold for 5 seconds or more?
YES
Replace the MAP sensor , then do the repair verification.
NO
Go to step 2.
- Problem verification
-1. Clear the DTC with the HDS.
-2. Start the engine. Hold the engine speed at 3000 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 deg.F (70 deg.C)
- Engine speed at 1400 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 , then do the repair verification.
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 2-2 and recheck.
- Repair verification (OBD STATUS check)
-1. Turn the vehicle to the ON mode.
-2. Reset the PCM with the HDS .
Reset PCM
-3. Do the PCM idle learn procedure .
-4. Start the engine. Hold the engine speed at 3000 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 deg.F (70 deg.C)
- Engine speed at 1400 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 -6. 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 DTC (PGM-FI)
Does the HDS indicate PASSED, FAILED, or NOT COMPLETED?
PASSED
Troubleshooting is complete. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.
FAILED
Go to step 1 and recheck.
NOT COMPLETED
Meet the test conditions, and check the OBD STATUS again.