Pinpoint Test AL: The In-Dash Computer Is Inoperative

Ford Work Solutions(TM)

Pinpoint Tests

Pinpoint Test AL: The In-Dash Computer Is Inoperative

Refer to Wiring Diagram Set 141 for schematic and connector information Diagrams By Number.

Normal Operation

The in-dash computer receives power and ground from the vehicle harness. It also monitors information over the Medium Speed Controller Area Network (MS-CAN) and without this information, it does not power-up.

This pinpoint test is intended to diagnose the following:

- Fuse
- Wiring, terminals or connectors
- In-dash computer



PINPOINT TEST AL: THE IN-DASH COMPUTER IS INOPERATIVE

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.

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AL1 CHECK THE IN-DASH COMPUTER VOLTAGE SUPPLY


- Ignition OFF.
- Disconnect: In-Dash Computer C2408a .
- Measure the voltage between the in-dash computer C2408a-1, circuit SBP39 (WH/RD), harness side and ground.




- Is the voltage greater than 10 volts?

Yes
GO to AL2.

No
VERIFY the Smart Junction Box (SJB) fuse 39 (20A) is OK. If OK, REPAIR the circuit. TEST the system for normal operation. If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short Diagrams By Number.

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AL2 CHECK THE IN-DASH COMPUTER GROUND CIRCUIT FOR CONTINUITY


- Measure the resistance between the in-dash computer C2408-13, circuit GD115 (BK/GY), harness side and ground.




- Is the resistance less than 5 ohms?

Yes
GO to AL3.

No
REPAIR the circuit. TEST the system for normal operation.

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AL3 CHECK MS-CAN CIRCUIT INTEGRITY TO THE IN-DASH COMPUTER


- Disconnect: Negative Battery Cable .
- Measure the resistance between the in-dash computer C2408b-15, circuit VDB06 (GY/OG), harness side and the Data Link Connector (DLC) C251-3, circuit VDB06 (GY/OG), harness side.




- Measure the resistance between the in-dash computer C2408b-16, circuit VDB07 (VT/OG), harness side and the DLC C251-11, circuit VDB07 (VT/OG), harness side.




- Are the resistances less than 5 ohms?

Yes
GO to AL4.

No
REPAIR the circuit in question for an open. TEST the system for normal operation.

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AL4 CHECK FOR CORRECT IN-DASH COMPUTER OPERATION


- Disconnect all the in-dash computer connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the in-dash computer connectors and make sure they seat correctly.
- Operate the system and determine if the concern is still present.
- Is the concern still present?

Yes
INSTALL a new in-dash computer. REFER to In-Dash Computer In-Dash Computer. 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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