Pinpoint Tests AA: The Message Center Is Not Operating Correctly
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
Pinpoint Test AA: The Message Center Is Not Operating Correctly
Refer to Wiring Diagram Set 60, Instrument Cluster (IC) for schematic and connector information. Diagrams By Number
Normal Operation
The message center uses the Instrument Cluster (IC) RUN/START voltage, which is supplied on circuit CBP29 (WH/VT) and the keep alive memory B+ voltage on circuit SBP26 (YE/RD). The IC logic ground is through circuit GD114 (BK/BU). The message center functionality is controlled through the message center switch and 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 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 IC which switch is pressed.
B1205-B1208:
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Message center switch
- IC
PINPOINT TEST AA: 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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AA1 RETRIEVE THE RECORDED DTCs FROM THE IC SELF-TEST
- Check for recorded DTCs from the IC self-test.
- Are any DTCs recorded?
Yes
GO to AA4.
No
GO to AA2.
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AA2 CHECK THE IC ODOMETER DISPLAY
- Ignition ON.
- Observe the odometer display in the message center.
- Is the odometer displayed?
Yes
GO to AA3.
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 IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.
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AA3 CARRY OUT THE IC 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 IC dealer test mode. Scroll through the displays until the message center displays all the segments.
- Does the message center display all the display segments?
Yes
GO to AA8.
No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.
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AA4 CHECK CIRCUITS CMC29 (GN/VT) AND RMC27 (WH/BN) FOR A SHORT TOGETHER
- Ignition OFF.
- Measure the resistance between the IC C220-24, circuit CMC29 (GN/VT), harness side and the IC C220-11, circuit RMC27 (WH/BN), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to AA5.
No
REPAIR the circuits. CLEAR the DTCs. REPEAT the self-test.
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AA5 CHECK CIRCUITS CMC29 (GN/VT) AND RMC27 (WH/BN) FOR A SHORT TO VOLTAGE
- 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. CLEAR the DTCs. REPEAT the self-test.
No
GO to AA6.
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AA6 CHECK CIRCUIT CMC29 (GN/VT) FOR AN OPEN AND A SHORT TO GROUND
- Ignition OFF.
- Disconnect: Message Center Switch C269.
- Measure the resistance between the IC C220-24, circuit CMC29 (GN/VT), harness side and the message center switch C269-5, 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 AA7.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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AA7 CHECK CIRCUIT RMC27 (WH/BN) FOR AN OPEN
- Measure the resistance between the IC C220-11, circuit RMC27 (WH/BN), harness side and the message center switch C269-4, circuit RMC27 (WH/BN), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to AA8.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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AA8 CHECK FOR VOLTAGE FROM THE IC
- Connect: IC C220.
- Ignition ON.
- Measure the voltage between the message center switch C269-5, circuit CMC29 (GN/VT), harness side and the message center switch C269-4, circuit RMC27 (WH/BN), harness side.
- Is the voltage approximately 5 volts or greater?
Yes
INSTALL a new message center switch. REFER to Message Center Switch Removal and Replacement. TEST the system for normal operation.
No
GO to AA9.
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AA9 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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