Dodge Ram Truck 1500-2500-3500. Manual — part 1136

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

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.

Did DTC P2608?

Yes

>> Refer to the INTERMITTENT CONDITION Symptom (Diagnostic Procedure). (Refer to 9 - ENGINE -

DIAGNOSIS AND TESTING)

No

>> Replace the ECM.

Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)

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ENGINE - ELECTRICAL DIAGNOSTICS - DIESEL

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

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ENGINE - ELECTRICAL DIAGNOSTICS - DIESEL

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

For the Engine circuit diagram (Refer to 9 - ENGINE - SCHEMATICS AND DIAGRAMS)

For a complete wiring diagram Refer to Section 8W.

•

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 SHORTED TO BATTERY NEGATIVE

ECM

INTERMITTENT CONDITION

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)

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 VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)

No

>> Go To 3

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ENGINE - ELECTRICAL DIAGNOSTICS - DIESEL

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

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 VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)

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 VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)

5.

HARNESS SHORTED

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

Is the resistance greater than 100k ohms?

Yes

>> Go To 6

No

>> Repair the shorted harness.

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 Symptom (Diagnostic Procedure). (Refer to 9 - ENGINE -

DIAGNOSIS AND TESTING)

No

>> Replace the ECM.

Perform POWERTRAIN VERIFICATION TEST VER - 1 (DIESEL). (Refer to 8 - ELECTRICAL/ELEC-
TRONIC CONTROL MODULES/ENGINE CONTROL MODULE - DIAGNOSIS AND TESTING)

DR/DH

ENGINE - ELECTRICAL DIAGNOSTICS - DIESEL

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