Has the vehicle been inspected for Diagnostic Trouble Codes (DTC's)?

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Go to Step 2

Refer to Engine Controls

1. Connect a scan tool to the DLC connector.
2. Drive the vehicle and compare the scan tool speed display to the instrument cluster speed display.

Do the 2 speeds correspond with each other?

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Go to Step 3

Go to Step 6

Are both the speedometer and the odometer inaccurate?

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Go to Step 4

Go to Step 7

Inspect the vehicle for the correct tire size, PCM calibration, and vehicle speed sensor application.

Are the component applications correct?

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Refer to VSS Diagnosis in Engine Controls

Go to Step 5

1. Replace the tires and the vehicle speed sensor or recalibrate the PCM with the correct application for the vehicle.
2. Inspect the system.

Is the symptom still present?

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Go to Step 6

System OK

Does one or more of the speed related features operate improperly along with the instrument cluster?

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Go to Step 10

Go to Step 7

Inspect CKT 389 for the following conditions:

Does a short, an open, or any signs of excessive resistance between the instrument cluster connector terminal D9 and the PCM connector C1 terminal 55 exist?

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Go to Step 8

Go to Step 9

1. Repair the following conditions:

•

The open

•	The excessive resistance

•	The short to ground

•	The short to battery voltage between the instrument cluster connector terminal D9 and the PCM connector C1 terminal 55.

2. Inspect the system.

Is the symptom still present?

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Go to Step 9

System OK

1. Inspect the instrument cluster for a poor connection.
2. If OK, replace the instrument cluster. Refer to Instrument Cluster Replacement .
3. Inspect the system.

Is the symptom still present?

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Go to Step 10

System OK

1. Identify any inoperative speed related components.
2. Disconnect all of the inoperative speed related components.
3. Use a DMM in order to probe between the inoperative component connector CKT 389 to ground.

If more than one component is inoperative, measure at any of the inoperative component connectors.

4. Turn the ignition switch to the RUN position.

Is the measured voltage within the specified range?

5 Volts or greater, or less than the battery voltage

Go to Step 12

Go to Step 11

1. Inspect CKT 389 for any of the following conditions:

•

An open

•	Any signs of excessive resistance

•	A short to ground

•	A short to battery voltage

2. If OK, inspect the modules for any internal shorts at the vehicle speed input terminals and replace as needed.
3. Inspect the system.

Is the symptom still present?

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Go to Step 12

System OK

1. Ensure that the DMM is connected between the inoperative component connector CKT 389 and ground.
2. Turn the ignition switch to the RUN position.
3. Rotate a drive wheel slowly by hand in the forward direction.

Does the voltage vary between the specified range?

1 Volt-2.5 Volts

Go to Step 13

Go to Step 14

1. Inspect the inoperative component for a poor connection.
2. If OK, replace the inoperative component.
3. Inspect the system.

Is the symptom still present?

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Go to Step 14

System OK

1. Reconnect all of the speed related components.
2. Disconnect the PCM connector C1.
3. Use a DMM in order to probe between the PCM connector C1 terminal 55 and ground.
4. Turn the ignition switch to the RUN position.

Is the measured voltage within the specified range?

5 Volts or greater, or less than the battery voltage

Go to Step 15

Go to Step 16

1. Inspect the PCM connector for a poor connection.
2. If OK, repair the powertrain control module. Refer to PCM Replacement in Engine Controls.
3. Inspect the system.

Is the symptom still present?

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Go to Step 16

System OK

1. Repair any of the following conditions in CKT 389:

•

The open

•	The excessive resistance

•	The short to ground

•	The short to the battery voltage between the inoperative component and the PCM harness connector.

2. Inspect the system.

Is the symptom still present?

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System OK