04 - 05 Chevrolet Colorado and GMC Canyon T-150 Possible No 4WD Shift Concern DTC C0327 - kw GMT355 NP1 light transfercase transfer case

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in the PI.

Service 4WD light on with codes C0327. The transfer case may not make any shifts.

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1. Verify the customer’s concern (The Service 4WD light should be on) and then pull codes with the Tech-2 (There will usually be a code e.g. DTC C0327-encoder motor circuit failure).
2. Before following eSI diagnostics,look for concerns in the following areas:

Wiring:

a). Connector C200: This connects the I/P harness to the body harness, behind the I/P left side above the brake pedal assembly on the lower A-pillar. Look for bent or backed out pins, and the connector not being fully seated.

b). Connector C105: This connects the engine harness to the body harness, in the engine compartment left side front near the battery. Look for bent or backed out pins, and the connector not being fully seated. Also look for wires with an open circuit inside the wiring insulation at the back side of the connector.

c). Encoder Motor connector: This connects to the encoder motor on the transfer case. Look for bent or backed out pins, and the connector not being fully seated.

d). Transfer Case Control Module connector: This connects to the TCCM located below the driver’s seat under the carpet. Look for bent or backed out pins, and the connector not being fully seated.

e). Transfer Case 2/4 Wheel Indicator Switch: This device is located on the transfer case. Look for damaged wiring at the switch (wires with an open circuit inside the wiring insulation).

Water Leaks:

a). Pass through seal (main body plug): This is where the I/P harness passes through the bulk head and connects to the body harness, behind the I/P left side above the brake pedal assembly on the lower A-pillar. Look for the main body plug not sealing properly at the bulk head-allowing water to leak down the inside of the bulk head, into the foot well and getting the TCCM wet.

b). Driver’s door weather strip seal: If the driver’s door is not closed securely or the weather strip is not sealing properly-then water can enter at the top of door, run down the B-pillar into the foot well and getting TCCM wet.

c). Park brake and hood release grommets: Located at bulk head under hood. Look for the pass through plug not sealing properly allowing water to leak down the inside of the bulk head, into the foot well and getting the TCCM wet.

3. Repair any concerns if found, then clear the codes using the Tech 2 and check for proper 4WD operation. If no concerns were found then clear the codes using the Tech 2 and check for proper 4WD operation. NOTE: To check for proper 4WD operation set the park brake, turn the ignition key to on, place the transmission in neutral. Using the 3-button 4WD accessory switch, shift from 2H-4H-4L then from 4L-4H-2H. If the concern returns then proceed to step #4.
4. Refer to the Diagnostic Information section under Transfer case-Isuzu T 150 in eSI.

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Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

(04 Chevrolet Colorado; GMC Canyon) and (05 Chevrolet Colorado; GMC Canyon)

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