P2608

P2608-HIGH VOLTAGE AT THE #2 INTAKE AIR HEATER RELAY





For complete wiring diagrams refer to Diagrams/Electrical.


- 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.







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 Intake Air Heater relay.

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.

Does this interrupt the clicking?

Yes

- Repair the poor connection.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 3

3. INTAKE AIR HEATER RELAY

Turn the ignition off.

Remove the Intake Air Heater Relay.

Check connectors - Clean/repair as necessary.

Measure the resistance between the signal and return posts of the intake air heater relay.

Is the resistance between 15 and 25 Ohms?

Yes

- Go To 4

No

- Replace the Intake Air Heater relay.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

4. SIGNAL CIRCUIT SHORTED TO BATTERY NEGATIVE

Disconnect the ECM harness connector(s).


NOTE: Check connectors - Clean/repair as necessary.

Measure the resistance between the signal circuit of the intake air heater relay and battery negative.

Is the resistance greater than 100 K ohms?

Yes

- Go To 5

No

- Repair signal circuit shorted to battery negative.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

5. HARNESS SHORTED

Measure the resistance between intake air heater relay signal circuit and all other ECM circuits in the ECM connectors.

Is the resistance greater than 100k ohms?

Yes

- Go To 6

No

- Repair the shorted harness.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

6. ECM

Reconnect the ECM harness connectors.

Turn the ignition on.

Disconnect the intake air heater relay signal wire.

Did DTC P0542 or 2608 set?

Yes

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition

No

- Replace the ECM.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test