P2609

P2609-NO VOLTAGE DROP SEEN FROM INTAKE AIR HEATERS





For complete wiring diagrams refer to Diagrams/Electrical.


- When Monitored:

First 15 seconds of engine operation.

- Set Condition:

The ECM does not detect a voltage drop on the intake air heater circuit.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test


1. INTAKE AIR HEATER OPEN

Measure the resistance between the intake air heater supply and ground terminal on each intake air heater.

Is the resistance less than 10 Ohms?

Yes

- Go To 2

No

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

2. INTAKE AIR HEATER GROUND OPEN

Measure the resistance of the intake air heater ground circuit between the intake air heater terminal and the intake manifold cover ground connection.


NOTE: The intake air heater circuit is grounded through a conductive gasket on the top and bottom of the air heater (grey colored gaskets).

Is the resistance less than 10 Ohms?

Yes

- Go To 3

No

- Repair the open Intake Air heater ground or replace both heater gaskets with the proper conductive gaskets.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

3. OPEN BATTERY CABLE FROM INTAKE AIR HEATER RELAY

Measure the resistance of the battery cable between the intake air heater and the intake air heater relay for both intake air heaters.

Is the resistance less than 10 Ohms?

Yes

- Go To 4

No

- Repair The open or high resistance battery cable from the intake heater relay to heater.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

4. BATTERY CABLE OPEN

Measure the resistance of the battery cable between the battery and the intake air heater relay for both relays.

Is the resistance less than 10 Ohms?

Yes

- Go To 5

No

- Replace the battery cable from the battery to the Intake Air Heater Relay.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

5. #1 INTAKE AIR HEATER RELAY

Disconnect the #1 intake air heater relay signal wire.

Connect a jumper wire from the signal terminal of the #1 intake air heater relay to battery positive.

Did the relay click when 12 volts was applied?

Yes

- Go To 6

No

- Replace #1 Intake Air Heater Relay.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

6. #2 INTAKE AIR HEATER RELAY

Disconnect the #2 intake air heater relay signal wire.

Connect a jumper wire from the signal terminal of the #2 intake air heater relay to battery positive.

Did the relay click when 12 volts was applied?

Yes

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition

No

- Replace #2 Intake Air Heater Relay.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test