P0237
P0237-MAP SENSOR VOLTAGE TOO LOWP0237 - Map Sensor Voltage Too Low:
WHEN MONITORED
With the ignition on and battery voltage greater than 10.4 volts.
SET CONDITION
The circuit voltage to the ECM falls below a calibrated threshold for a certain period of time.
POSSIBLE CAUSES
- Other DTC's
- (K37) Signal circuit shorted to (K916) sensor return circuit
- (F855) 5-Volt supply circuit shorted to (K916) sensor return circuit
- MAP sensor
- (K37) Signal circuit open
- (F855) 5-Volt supply circuit open
- MAP sensor (K37) signal circuit short to ground
- ECM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.
Diagnostic Test
1. OTHER DTC'S
Turn the ignition on.
With the scan tool, read the Engine DTC's.
Q: Is there a 5-volt Supply DTC set?
YES: Refer to symptom list for problems related to the 5-volt Supply DTC. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Go To 2
2. HIGH VOLTAGE
Turn the ignition off.
Disconnect the Map sensor harness connector.
Check connectors - Clean/repair as necessary.
Turn the ignition on.
Measure the voltage between the (F855) 5-volt supply circuit and sensor (K916)) return circuit of the Map sensor harness connector.
Q: Is the voltage between 4.5 and 5.5 volts?
YES: Go To 3
NO: Go To 4
3. MAP SENSOR
While monitoring the scan tool, jumper the (F855) 5-volt supply circuit to the (K37) signal circuit in the Map sensor harness connector.
Q: Did the P0238-MAP SENSOR VOLTAGE TOO HIGH, DTC set?
YES: Replace the MAP sensor. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Go To 4
4. (K37) SIGNAL CIRCUIT SHORTED TO (K916)) SENSOR RETURN CIRCUIT
Turn the ignition off.
Disconnect the ECM harness 60 pin connector.
NOTE: Check connectors - Clean/repair as necessary.
Measure the resistance between the (K37) signal circuit and (K916)) sensor return circuit in the MAP sensor harness connector.
Q: Is the resistance greater than 100 K Ohms?
NO: Repair (K37) signal circuit shorted to (K916)) sensor return circuit or replace harness. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
YES: Go To 5
5. (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO (K916)) SENSOR RETURN CIRCUIT
Measure the resistance between the (F855) 5-volt supply circuit and (K916)) sensor return circuit in the MAP sensor harness connector.
Q: Is the resistance greater than 100 K Ohms?
NO: Repair (F855) 5-volt supply circuit shorted to (K916)) sensor return circuit or replace harness. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
YES: Go To 6
6. (K37) SIGNAL CIRCUIT OPEN
Measure the resistance between the signal (K37) circuit in the Map sensor harness connector with the (K37) signal circuit in the ECM harness connector.
Q: Is the resistance less than 10 Ohms?
YES: Go To 7
NO: Repair or replace the engine harness. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
7. (F855) 5-VOLT SUPPLY CIRCUIT OPEN
Measure the resistance between the (F855) 5-volt supply circuit in the Map sensor harness connector with the (F855) 5-volt supply circuit in the ECM harness connector.
Q: Is the resistance less than 10 Ohms?
YES: Go To 8
NO: Repair or replace the engine harness. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
8. MAP SENSOR SIGNAL (K37) CIRCUIT SHORTED TO GROUND
Measure the resistance between the MAP Sensor Signal (K37) circuit and the Battery negative terminal.
Q: Is the resistance above 100k ohms?
YES: Go To 9
NO: Repair the MAP Sensor (K37) Signal circuit for a short to ground. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
9. (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO (K916)) RETURN CIRCUIT OR GROUND
Measure the resistance between the (F855) 5-volt supply circuit in the sensor harness connector and battery negative.
Q: Is the resistance above 100k ohms?
YES: Go To 10
NO: Test Complete.
10. ECM
Reconnect the ECM harness 60 pin connector.
While monitoring the scan tool, jumper the (F855) 5-volt supply circuit to the (K37) signal circuit in the map sensor harness connector.
Q: Did the P0238-MAP SENSOR VOLTAGE TOO HIGH, DTC set?
YES: Test Complete.
NO: Replace and program the ECM in accordance with the Service Information. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1