Pinpoint Tests AC: The Message Center Is Not Operating Correctly
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
Pinpoint Test AC: The Message Center Is Not Operating Correctly
Refer to Wiring Diagram Set 60, Instrument Cluster for schematic and connector information. Diagrams By Number
Normal Operation
The message center uses the Instrument Panel Cluster (IPC) RUN/START voltage, which is supplied on circuit CBP29 (WH/VT) and the keep alive memory B+ voltage on circuit SBP26 (YE/RD). The IPC logic ground is through circuit GD114 (BK/BU). The message center functionality is controlled through the message center switch and is hardwired to the IPC through input circuit CMC29 (GN/VT) and return circuit RMC27 (WH/BN).
There are 3 message center switch buttons with each button operating a switch that uses different resistance values. The IPC sends out a reference voltage to the message center switch on circuit CMC29 (GN/VT) and monitors the voltage drop when a message center switch button is pressed. The voltage drop will vary depending upon the resistance of each button, providing a specific indication to the IPC which switch is pressed.
- DTC B1A82:11 (External Trip Switch: Circuit Short to Ground) - a continuous DTC that sets in the IPC if the IPC detects a short to ground on circuit CMC29 (GN/VT).
- DTC B1A82:13 (External Trip Switch: Circuit Open) - a continuous DTC that sets in the IPC if the IPC detects an open on circuit CMC29 (GN/VT).
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Front Controls Interface Module (FCIM)
- HVAC module
- IPC
PINPOINT TEST AC: THE MESSAGE CENTER IS NOT OPERATING CORRECTLY
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
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AC1 RETRIEVE THE RECORDED DTCs FROM THE IPC SELF-TEST
- Check for recorded DTCs from the IPC self-test.
- Are any DTCs recorded?
Yes
GO to AC4.
No
GO to AC2.
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AC2 CHECK THE IPC ODOMETER DISPLAY
- Ignition ON.
- Observe the odometer display in the message center.
- Is the odometer displayed?
Yes
GO to AC3.
No
If the display is blank, PRESS the INFO button to see if the message center was previously set to the blank display.
If the display remains blank, INSTALL a new IPC. REFER to Instrument Panel Cluster (IPC) Instrument Panel Cluster (IPC). TEST the system for normal operation.
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AC3 CARRY OUT THE IPC DEALER TEST MODE
- NOTE: The all segments display is the second button press after entering the dealer test mode immediately following the gauge test.
- Enter the IPC dealer test mode. Scroll through the displays until the message center displays all the segments.
- Does the message center display all the illuminate segments?
Yes
GO to AC7.
No
INSTALL a new IPC. REFER to Instrument Panel Cluster (IPC) Instrument Panel Cluster (IPC). TEST the system for normal operation.
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AC4 CHECK CIRCUITS CMC29 (GN/VT) AND VMC29 (YE) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: IPC C220.
- Ignition ON.
- Measure the voltage between the IPC C220-24, circuit CMC29 (GN/VT), harness side and ground; and between the IPC C220-11, circuit RMC27 (WH/BN), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.
No
GO to AC5.
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AC5 CHECK CIRCUIT CMC29 (GN/VT) FOR AN OPEN AND SHORT TO GROUND
- Ignition OFF.
- Disconnect: FCIM C2402b (With Navigation) or HVAC Module C228c (Without Navigation).
- Measure the resistance between the IPC C220-24, circuit CMC29 (GN/VT), harness side and the FCIM C2402b-3 (with navigation) or the HVAC module C228c-3 (without navigation), circuit CMC29 (GN/VT), harness side; and between the IPC C220-24, circuit CMC29 (GN/VT), harness side and ground.
- Is the resistance less than 5 ohms between the IPC and the FCIM (with navigation) or HVAC module (without navigation), and greater than 10,000 ohms between the IPC and ground?
Yes
GO to AC6.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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AC6 CHECK CIRCUIT RMC27 (WH/BN) FOR AN OPEN
- Measure the resistance between the IPC C220-11, circuit RMC27 (WH/BN), harness side and the FCIM C2402b-4 (with navigation) or the HVAC module C228c-4 (without navigation), circuit RMC27 (WH/BN), harness side.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new HVAC module (without navigation) or FCIM (with navigation). TEST the system for normal operation.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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AC7 CHECK FOR VOLTAGE FROM THE IPC
- Connect: IPC C220.
- Disconnect: FCIM C2402b (With Navigation) or HVAC Module C228c (Without Navigation).
- Ignition ON.
- Measure the voltage between the FCIM C2402b-3 (with navigation) or the HVAC module C228c-3 (without navigation), circuit CMC29 (GN/VT), harness side and the FCIM C2402b-4 (with navigation) or the HVAC module C228c-4 (without navigation), circuit RMC27 (WH/BN), harness side.
- Is the voltage approximately 5 volts or greater?
Yes
For the HVAC module, GO to AC8.
For the FCIM, GO to AC9.
No
INSTALL a new IPC. REFER to Instrument Panel Cluster (IPC) Instrument Panel Cluster (IPC). TEST the system for normal operation.
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AC8 CHECK FOR CORRECT HVAC MODULE OPERATION
- Disconnect the HVAC module connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the HVAC module connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new HVAC module. TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.
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AC9 CHECK FOR CORRECT FCIM OPERATION
- Disconnect the FCIM connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the FCIM connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new FCIM. TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.
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