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 speed display to the instrument cluster speed display.
2. Drive the vehicle and compare the scan tool speed display to the instrument cluster speed display.

Do the two speeds correspond with one another?

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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, or 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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System OK

Are any of the speed related features inoperative along with the instrument cluster?

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Go to Step 10

Go to Step 7

Inspect CKT 389 for any of the following conditions:

Does an open, any excessive resistance, a short to ground, or a short to battery voltage between the digital speedometer module connector terminal B and the PCM connector C1 terminal 55 exist in CKT 389?

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Go to Step 8

Go to Step 9

1. Repair the following conditions in CKT 389:

•

The open

•	The excessive resistance

•	The short to ground

•	The short to the battery voltage between the digital speedometer module connector terminal B and the PCM connector C1 terminal 55.

2. Inspect the system.

Is the symptom still present?

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System OK

1. Inspect the digital speedometer module for a poor connection.
2. If OK, replace the digital speedometer module. Refer to Digital Speedometer Module Replacement.

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System OK

1. Identify any inoperative speed related component.
2. Disconnect all of the inoperative speed related components.
3. Connect a DMM from the inoperative component connector CKT 389 to ground. If more than one of the components are inoperative, measure at any inoperative component connector.
4. Turn the ignition 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 the following conditions:

•

An open

•	Any excessive resistance

•	A short to ground

•	A short in the battery voltage.

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

Is the symptom still present?

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System OK

1. Ensure that the DMM is connected from 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 measured voltage vary from the specified value

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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System OK

1. Reconnect the speed related components.
2. Disconnect the PCM connector C1.
3. Use the 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 value?

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. replace the powertrain control module. Refer to PCM Replacement in Engine Controls.
3. Inspect the system.

Is the symptom still present?

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System OK

1. Repair the following conditions in CKT 389:

•

The open

•	The excessive resistance

•	The short to ground

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

2. Inspect the system.

Is the symptom still present?

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System OK