B10B4

B10B4-CABIN HEATER 1 CONTROL CIRCUIT LOW (FCM)





For a complete wiring diagram Refer to Diagrams/Electrical

- When Monitored:

With the ignition on, the ASD Relay energized, and the PTC No. 1 Relay command on.

- Set Condition:

If the Front Control Module (FCM) detects that the (K360) PTC No. 1 Relay Control circuit is shorted to ground.





Diagnostic Test

1.VERIFY THAT THE DTC IS ACTIVE

WARNING: WHEN THE ENGINE IS OPERATING, DO NOT STAND IN A DIRECT LINE WITH THE FAN. DO NOT PUT YOUR HANDS NEAR THE PULLEYS, BELTS OR FAN. DO NOT WEAR LOOSE CLOTHING.

NOTE: If the FCM detects and stores a DTC, the FCM also stores the environmental conditions under which the DTC was set.

NOTE: Before erasing stored DTCs, record these conditions. Attempting to duplicate these conditions may assist when checking for an active DTC.

Turn the ignition on.

With the scan tool, erase FCM DTCs.

With the scan tool, actuate the PTC No. 1 Relay.

Monitor the scan tool for at least two minutes.

With the scan tool, read FCM DTCs.

Is the status Active for this DTC?

Yes

- Go To 2

No

- Check for an intermittent condition by inspecting the related wiring harness for chaffed, pierced, pinched, and partially broken wires. Also, inspect the related connectors for broken, bent, pushed out, spread, corroded, or contaminated terminals.

2.CHECK (K342) FUSED ASD RELAY OUTPUT CIRCUIT FOR AN OPEN OR HIGH RESISTANCE





Turn the ignition off.

Remove the PTC No. 1 Relay.

Turn the ignition on.

Using a 12 volt test light connected to ground, check the (K342) Fused ASD Relay Output circuit in the PTC No. 1 Relay connector.

NOTE: The test light should illuminate brightly. Compare the brightness to that of a direct connection to the battery.

Does the test light illuminate brightly?

Yes

- Go To 3

No

- Repair the (K342) Fused ASD Relay Output circuit for an open or high resistance.
- Perform the BODY VERIFICATION TEST VER 1. Body Verification Test

3.CHECK (K360) PTC NO. 1 RELAY CONTROL CIRCUIT FOR A SHORT TO GROUND





Turn the ignition off.

Disconnect the FCM from the Power Module.

Measure the resistance between ground and the (K360) PTC No. 1 Relay Control circuit in the PTC No. 1 Relay connector.

Is the resistance above 10.0 ohms?

Yes

- Go To 4

No

- Repair the (K360) PTC No. 1 Relay Control circuit for a short to ground.
- Perform the BODY VERIFICATION TEST VER 1. Body Verification Test

4.CHECK (K360) PTC NO. 1 RELAY CONTROL CIRCUIT FOR AN OPEN OR HIGH RESISTANCE





Measure the resistance of the (K360) PTC No. 1 Relay Control circuit between the PTC No. 1 Relay connector and the FCM connector.

Is the resistance below 10.0 ohms?

Yes

- Go To 5

No

- Repair the (K360) PTC No. 1 Relay Control circuit for an open or high resistance.
- Perform the BODY VERIFICATION TEST VER 1. Body Verification Test

5.CHECK PTC NO. 1 RELAY





Install the FCM.

Install a substitute PTC No. 1 Relay in place of the vehicle's PTC No. 1 Relay.

Turn the ignition on.

With the scan tool, erase FCM DTCs.

With the scan tool, actuate the PTC No. 1 Relay.

Monitor the scan tool for at least two minutes.

With the scan tool, read FCM DTCs.

Is the status Active for this DTC?

Yes

- Go To 6

No

- Replace the PTC No. 1 Relay.
- Perform the BODY VERIFICATION TEST VER 1. Body Verification Test

6.INSPECT RELATED WIRING & CHECK FOR TSBs

Turn the ignition off.

Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the PTC No. 1 Relay and the FCM.

Look for any chafed, pierced, pinched, or partially broken wires.

Look for broken, bent, pushed out or corroded terminals.

Refer to any Technical Service Bulletins that may apply.

Were any problems found?

Yes

- Repair as necessary.
- Perform the BODY VERIFICATION TEST VER 1. Body Verification Test

No

- Replace the FCM.
- Perform the BODY VERIFICATION TEST VER 1. Body Verification Test