Pinpoint Tests AD: The Message Center Is Not Operating Correctly
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
Pinpoint Test AD: 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 is located in the center of the Instrument Cluster (IC) between the tachometer and the speedometer. The message center is integral to the IC and uses the same voltage supply as the IC. The RUN/START voltage is supplied to the IC on circuit CBP29 (WH/VT) and the keep alive B+ voltage is received on circuit SBP26 (YE/RD). The IC ground is received through circuit GD115 (BK/GY).
The message center functionality is controlled through the message center switch, which is hardwired to the IC 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 IC sends out a reference voltage to the message center switch on the input circuit and monitors the voltage drop when a message center switch button is pressed. The voltage drop varies depending upon the resistance of each button, providing a specific indication to the IC which switch is pressed.
- DTC B1209 ( EIC Switch-2 Assembly Circuit Failure) - a continuous memory and on-demand DTC that sets if the IC detects any of the message center switch buttons stuck during the self-test.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Message center switch
- IC
PINPOINT TEST AD: 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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AD1 CHECK THE MESSAGE CENTER DISPLAY OPERATION USING THE SCAN TOOL
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC DataLogger.
- Select the IC display segment (ALL_SEG) active command and command the display segments on. Observe the message center display.
- Does the message center display illuminate all segments?
Yes
GO to AD2.
No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.
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AD2 RETRIEVE THE RECORDED DTCs FROM THE IC SELF-TEST
- Retrieve the recorded IC DTCs from the self-test.
- Is DTC B1209 recorded?
Yes
INSTALL a new message center switch. REFER to Message Center Switch Service and Repair.
No
GO to AD3.
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AD3 CHECK CIRCUITS CMC29 (GN/VT) AND RMC27 (WH/BN) FOR A SHORT TO VOLTAGE
- Ignition OFF.
- Disconnect: IC C220.
- Ignition ON.
- Measure the voltage between the IC C220-24, circuit CMC29 (GN/VT), harness side and ground; and between the IC C220-11, circuit RMC27 (WH/BN), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit in question. TEST the system for normal operation.
No
GO to AD4.
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AD4 CHECK CIRCUIT CMC29 (GN/VT) FOR AN OPEN AND SHORT TO GROUND
- Ignition OFF.
- Disconnect: Message Center Switch C253.
- Measure the resistance between the IC C220-24, circuit CMC29 (GN/VT), harness side and the message center switch C253-3, circuit CMC29 (GN/VT), harness side; and between the IC C220-24, circuit CMC29 (GN/VT), harness side and ground.
- Is the resistance less than 5 ohms between the IC and the message center switch, and greater than 10,000 ohms between the IC and ground?
Yes
GO to AD5.
No
REPAIR the circuit. TEST the system for normal operation.
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AD5 CHECK CIRCUIT RMC27 (WH/BN) FOR AN OPEN AND SHORT TO GROUND
- Measure the resistance between the IC C220-11, circuit RMC27 (WH/BN), harness side and the message center switch C253-2, circuit RMC27 (WH/BN), harness side; and between the IC C220-11, circuit RMC27 (WH/BN), harness side and ground.
- Is the resistance less than 5 ohms between the IC and the message center switch, and greater than 10,000 ohms between the IC and ground?
Yes
GO to AD6.
No
REPAIR the circuit. TEST the system for normal operation.
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AD6 CHECK FOR VOLTAGE FROM THE IC
- Connect: IC C220.
- Ignition ON.
- Measure the voltage between the message center switch C253-3, circuit CMC29 (GN/VT), harness side and the message center switch C253-2, circuit RMC27 (WH/BN), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
INSTALL a new message center switch. REFER to Message Center Switch Service and Repair. TEST the system for normal operation.
No
GO to AD7.
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AD7 CHECK FOR CORRECT IC OPERATION
- Disconnect the IC connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the IC 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 IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). 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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