P2609

P2609-INTAKE AIR HEATER SYSTEM PERFORMANCE





For complete wiring diagrams refer to Diagrams/Electrical.


Theory of Operation

The intake air heater is integrated into the intake manifold cover. The air heater element is used to heat incoming air into the intake manifold. This is done to help engine starting and improve driveability with cool or cold outside temperatures. Electrical supply for the air heater element is controlled by the ECM through the air heater relay. One heavy duty cable connects the air heater element to the air heater relay. This cable will supply 12 volts to air heater elements. The ECM will light the MIL lamp when the diagnostic runs and fails in two consecutive drive cycles. The ECM will turn off the MIL lamp when the diagnostic runs and passes in 4 consecutive drive cycles.

- 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.

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.

Is the resistance less than 10 Ohms?

Yes

- Go To 3

No

- Repair the open Intake Air heater ground.
- 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.

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 the relay.

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. INTAKE AIR HEATER RELAY

Disconnect the intake air heater relay signal wire.

Connect a jumper wire from the signal terminal of the 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 Intake Air Heater Relay.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test