Pinpoint Tests AH: The Message Center Is Not Operating Correctly
Instrumentation, Message Center and Warning Chimes
Pinpoint Tests
Pinpoint Test AH: 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 message center uses IC RUN/START, keep alive B+ voltage and IC ground.
The message center functionality is controlled through the message center switch, which is hardwired to the IC through input and return circuits. 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 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.
- 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.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Message center switch
- IC
PINPOINT TEST AH: 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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AH1 RETRIEVE THE RECORDED DTCs FROM THE IC SELF-TEST
- Retrieve the recorded IC DTCs from the self-test.
- Is DTC B1206 or DTC B1208 recorded?
Yes
GO to AH4.
No
GO to AH2.
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AH2 CHECK THE MESSAGE CENTER SWITCH INPUT TO THE IC
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: IC DataLogger .
- Select and monitor the IC message center PIDs (INFOSW, SETUPSW and RES_SW) while pressing the INFO, SETUP and RESET switch.
- Does the PID agree with each of the button positions (pressed and released)?
Yes
GO to AH3.
No
INSTALL a new message center switch. REFER to Message Center Switch Removal and Replacement. TEST the system for normal operation.
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AH3 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
The message center is operating correctly at this time. If the concern is related to a specific warning message, GO to Symptom Chart - Information and Message Center. Instrumentation, Message Center and Warning Chimes
No
GO to AH8.
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AH4 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 AH5.
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AH5 CHECK THE MESSAGE CENTER SIGNAL AND RETURN CIRCUITS 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 AH6.
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AH6 CHECK THE MESSAGE CENTER SIGNAL CIRCUIT 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 AH7.
No
REPAIR circuit CMC29 (GN/VT) for an open or a short to ground. CLEAR the DTCs. REPEAT the self-test.
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AH7 CHECK THE MESSAGE CENTER RETURN CIRCUIT 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 circuit VMC29 (YE) for an open. CLEAR the DTCs. REPEAT the self-test.
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AH8 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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