P2607

P2607-LOW VOLTAGE AT THE #2 INTAKE AIR HEATER RELAY

P2607 - Low Voltage At The #2 Intake Air Heater Relay:

WHEN MONITORED
When the ignition is on.

SET CONDITION
When the signal from the #2 intake air heater output does not match the signal from the #2 intake air heater feedback.

POSSIBLE CAUSES
- Loose connection
- Intake air heater relay
- Signal circuit open from relay to ECM
- Signal circuit shorted to battery negative
- ECM
- Intermittent condition

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test

1. RELAY CLICKING
Ignition on, engine not running.
With the scan tool, actuate the #1 Intake Air Heater.

Q: Can you hear the Relay clicking?

YES: Go To 2
NO: Go To 3

2. LOOSE CONNECTION
While the relay is clicking , wiggle the wiring harness and connectors.

Q: Does this interrupt the clicking?

YES: Repair the poor connection. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Go To 3

3. INTAKE AIR HEATER RELAY
Turn the ignition off.
Remove the Intake Air Heater #1 Relay.
Check connectors - Clean/repair as necessary.
Measure the resistance between the signal and return posts of the intake air heater relay.

Q: Is the resistance between 15 and 25 Ohms?

YES: Go To 4
NO: Replace the Intake Air Heater #1 relay. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1

4. SIGNAL CIRCUIT OPEN FROM RELAY TO ECM
Disconnect the ECM harness connectors.
Check connectors - Clean/repair as necessary.
Measure the resistance of the intake air heater relay signal circuit between the ECM connector and the intake air heater relay connector.

Q: Is the resistance less than 10 Ohms?

YES: Go To 5
NO: Repair the open signal circuit from PDC to ECM harness connector. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1

5. RETURN CIRCUIT SHORTED TO BATTERY NEGATIVE
Measure the resistance of the return circuit between the intake air heater relay connector and battery negative.

Q: Is resistance less than 10 ohms?

YES: Go To 6
NO: Repair the return circuit shorted to battery negative.

6. SIGNAL CIRCUIT SHORTED TO BATTERY NEGATIVE
Measure the voltage between the signal circuit of the intake air heater relay and battery negative.

Q: Is the voltage greater than 1 volts?

YES: Repair the signal circuit shorted to Battery negative. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1
NO: Go To 7

7. ECM
Reconnect the ECM harness connectors.
Disconnect the intake air heater relay signal wire and use a jumper to connect it to battery negative.
Turn the ignition on.
With the scan tool, read DTCs.

Q: Did DTC P2608?

YES: Refer to the INTERMITTENT CONDITION Symptom (Diagnostic Procedure).
NO: Replace the ECM. Perform the POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). Powertrain Verification Test - Ver 1