Pinpoint Tests AG: The Message Center Is Not Operating Correctly
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
Pinpoint Test AG: The Message Center Is Not Operating Correctly
Normal Operation
The message center is located in the center of the Instrument Cluster (IC) between the tachometer and the speedometer in the message center display area. 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 logic ground is through circuit GD112 (BK/GN) and the bulb ground is through circuit GD114 (BK/BU).
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 VMC29 (YE). 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 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.
- DTC B1206 (EIC Switch-1 Assembly Circuit Open) - a continuous and on-demand DTC that sets when the IC detects an open on the message center switch input, circuit CMC29 (GN/VT).
- DTC B1208 (EIC Switch-1 Assembly Circuit Short to Ground) - a continuous and on-demand DTC that sets when the IC detects a short to ground on the message center switch input, circuit CMC29 (GN/VT).
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Message center switch
- IC
PINPOINT TEST AG: 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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AG1 RETRIEVE THE RECORDED DTCs FROM THE IC SELF-TEST
- Retrieve the recorded IC DTCs from the self-test.
- Is DTC B1206 or B1208 recorded?
Yes
GO to AG5.
No
GO to AG2.
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AG2 CHECK THE INSTRUMENT CLUSTER (IC) ODOMETER OPERATION
- Ignition ON.
- Observe the odometer display in the message center.
- Is the odometer displayed?
Yes
GO to AG3.
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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AG3 CHECK THE MESSAGE CENTER DISPLAY OPERATION USING THE SCAN TOOL
- Enter the following diagnostic mode on the scan tool: IC DataLogger.
- Select the IC display segment control (ALL_SEG) active command. Command the display segments on. Observe the message center display.
- Does the message center display illuminate all segments?
Yes
GO to AG4.
No
INSTALL a new IC. REFER to Instrument Cluster (IC) Instrument Cluster (IC). TEST the system for normal operation.
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AG4 CHECK FOR VOLTAGE FROM THE IC
- Connect: IC C269.
- Ignition ON.
- Measure the voltage between the message center switch C269-3, circuit CMC29 (GN/VT), harness side and the message center switch C269-2, circuit VMC29 (YE), harness side.
- Is the voltage greater than 10 volts?
Yes
INSTALL a new message center switch. REFER to Message Center Switch Removal and Replacement. TEST the system for normal operation.
No
GO to AG8.
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AG5 CHECK CIRCUITS CMC29 (GN/VT) AND VMC29 (YE) 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 VMC29 (YE), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit in question. CLEAR the DTCs. REPEAT the self-test.
No
GO to AG6.
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AG6 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 C269-3, 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 AG7.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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AG7 CHECK CIRCUIT VMC29 (YE) FOR AN OPEN
- Measure the resistance between the IC C220-11, circuit VMC29 (YE), harness side and the message center switch C269-2, circuit VMC29 (YE), harness side.
- Is the resistance less than 5 ohms?
Yes
INSTALL a new message center switch. REFER to Message Center Switch Removal and Replacement. CLEAR the DTCs. REPEAT the self-test.
No
REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test.
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AG8 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.
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