Pinpoint Test S: DTC P189A:00
Electronic Locking Differential (ELD) System
Pinpoint Tests
Pinpoint Test S: DTC P189A:00
Refer to Wiring Diagram Set 34, Four-Wheel Drive Systems for schematic and connector information. Diagrams By Number
Normal Operation
When the Mode Select Switch (MSS) is engaged to lock the rear differential, a Pulse Width Modulated (PWM) signal is sent to the Electronic Locking Differential (ELD) field coil by the Transfer Case Control Module (TCCM) through the differential lock control circuit. This signal is a PWM signal which is initially 98% duty cycle to lock the differential and decreases to 40% duty cycle once the differential is locked. When the differential is starting to lock, the graphic in the Instrument Panel Cluster (IPC) message center starts to blink. When the differential is fully locked, the graphic illuminates steady.
- DTC P189A:00 (Axle Disconnect Input Switch Circuit Low: No Sub Type Information) - When not in locking mode, the TCCM senses the resistance to ground on circuit CCF32 and if the differential is always engaged. This DTC only displays during the self-test function.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- MSS
- TCCM
PINPOINT TEST S: DTC P189A:00
NOTE: Make sure the battery is fully charged before carrying out this pinpoint test.
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S1 CHECK THE MSS
- Ignition OFF.
- Disconnect: MSS C284.
- Set the Mode Select Switch (MSS) in 2H (Electronic Shift-On-The-Fly (ESOF)
- Set the Mode Select Switch (MSS) in OFF (2-Wheel Drive (2WD) or MSOS)
- Measure the resistance between MSS C284 pins 1 and 2, component side, while the MSS is in 2H or OFF position.
- Are the resistance values between 22-27 ohms?
Yes
GO to S2.
No
INSTALL a new MSS. REFER to Mode Select Switch (MSS) Mode Select Switch (MSS). CLEAR the DTCs. TEST the system for normal operation. REPEAT the self-test.
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S2 CHECK THE ELD MODE CIRCUIT FOR A SHORT TO GROUND
- Ignition OFF.
- Disconnect: TCCM C2371A.
- Measure the resistance between TCCM C2371A-15, circuit CCF32 (WH/GN), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to S3.
No
REPAIR circuit CCF32 (WH/GN). CLEAR the DTCs. TEST the system for normal operation. REPEAT the self-test.
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S3 CHECK FOR CORRECT TCCM OPERATION
- Ignition OFF.
- Disconnect all TCCM connectors.
- Check for:
- corrosion
- pushed-out pins
- Connect all TCCM connectors and make sure they are seated correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new TCCM. REFER to Transfer Case Control Module (TCCM) Service and Repair. TEST the system for normal operation. REPEAT the self-test.
No
The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector. CLEAR the DTCs. TEST the system for normal operation. REPEAT the self-test.
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