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Speed Control Switch 1 Stuck (ETC)






P1593-SPEED CONTROL SWITCH 1 STUCK (ETC)





For a complete wiring diagram refer to Diagrams/Electrical.

- When Monitored:

Ignition on.

- Set Condition:

Cruise Switch inputs are not coherent with each other. Example: PCM is reading Switch No.1 as Accel and Switch No.2 as Coast at the same time. One trip fault.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test

1. ACTIVE DTC

Ignition on, engine not running.

NOTE: This DTC may be the result of pressing two Speed Control Switch buttons simultaneously for more than 450 msec.

Ask the customer if it is possible that two buttons were pressed at the same time before this DTC set. If this is the case, no repair is necessary.

Is the DTC Active at this time?

Yes

- Go To 2

No

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition

2. SPEED CONTROL ON/OFF SWITCH

With the scan tool, monitor the Speed Control Switch voltage.

Disconnect the Speed Control On/Off Switch harness connector.

Did the voltage change to above 4.8 volts?

Yes

- Replace the Speed Control On/Off Switch.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 3

3. SPEED CONTROL RESUME/ACCEL SWITCH

With the scan tool, monitor the Speed Control Switch voltage.

Disconnect the Speed Control Resume/Accel Switch harness connector.

Did the voltage change to above 4.8 volts?

Yes

- Replace the Speed Control Resume/Accel Switch.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 4

4. SPEED CONTROL SWITCHES

Turn the ignition off.

Remove and disconnect the Speed Control Switches from the steering wheel.

Measure the resistance across each Speed Control Switch.

Monitor the ohmmeter while pressing each function button on each switch.

The following resistance specs are taken between terminals (V372) S/C Switch No.2 Signal and (V397) S/C Switch Return circuits of the Switch when holding the switch button in the following position.

Not pressing any switch - 20.5 kohms

On/Off - 8.87 kohms

Set - 0.825 kohms

Coast - 0.47 kohms

Cancel - 3.92 kohms

Resume/Accel - 1.87 kohms

The following resistance specs are taken between terminals (V371) S/C Switch No.1 Signal and (V397) S/C Switch Return circuits of the Switch when holding the switch button in the following position

Not pressing any switch - 20.5 kohms

On/Off - 0.47 kohms

Set - 5.49 kohms

Coast - 2.94 kohms

Cancel - 1.24 kohms

Resume/Accel - 15.4 kohms

Does the function on the Speed Control Switches have the correct resistance value?

Yes

- Go To 5

No

- Replace the Speed Control Switch that had the incorrect resistance value.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

5. S/C SWITCH SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE









Disconnect the C3 PCM harness connector.

Measure the voltage on the (V371) and (V372) S/C Switch Signal circuits at both Speed Control harness connectors.

Is the voltage above 5.0 volts?

Yes

- Repair the short to battery voltage in the (V371) or (V372) S/C Switch Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 6

6. STEERING COLUMN CONTROL MODULE

Turn the ignition off.

Disconnect the C1 and C3 SCCM harness connectors.

Measure the resistance of the (V371/V71) and (V372/V72) S/C Switch Signal circuits between the C1 and C3 SCCM connectors.

Measure the resistance of the (V397/V937) Switch Return circuit between the C1 and C3 SCCM connectors.

Is the resistance above 5.0 ohms?

Yes

- Replace the SCCM.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 7
-
NOTE: Connect the Steering Column Control Module harness connectors before continuing.

7. S/C SWITCH SIGNAL CIRCUIT OPEN









CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

Measure the resistance of the (V371/V71) and (V372/V72) S/C Switch Signal circuits from both Speed Control harness connectors to the appropriate terminals of special tool #8815.

Is the resistance below 5.0 ohms for each measurement?

Yes

- Go To 8

No

- Repair the excessive resistance in the (V371/V71) or (V372/V72) S/C Switch Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

8. (V397/V937) SWITCH RETURN CIRCUIT OPEN





NOTE: The measurement must be taken from both Speed Control Switch harness connectors.

Measure the resistance of the (V397/V937) Switch Return circuit from both Speed Control harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms for both measurements?

Yes

- Go To 9

No

- Repair the excessive resistance in the (V397/V937) Switch Return circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

9. S/C SWITCH SIGNAL CIRCUITS SHORTED TO THE (V397/V937) SWITCH RETURN CIRCUIT









Measure the resistance between the (V397) Switch Return circuit and both of the (V371) and (V372) S/C Switch Signal circuits in the Speed Control harness connector.

Is the resistance below 5.0 ohms?

Yes

- Repair the short between the (V397/V937) Switch Return circuit and the (V371/V71) or (V372/V72) S/C Switch Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 10

10. (V371/V71) S/C SWITCH NO.1 SIGNAL CIRCUIT SHORTED TO THE (V372/V72) S/C SWITCH NO.2 SIGNAL CIRCUIT





Measure the resistance between the (V371/V71) S/C Switch No.1 Signal circuit and the (V372/72) S/C Switch No.2 Signal circuit at both Speed Control harness connectors.

Is the resistance below 100 ohms for each circuit?

Yes

- Repair the short between the (V372/V72) S/C Switch No.2 Signal circuit and the (V371) S/C Switch No.1 Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 11

11. S/C SWITCH SIGNAL CIRCUITS SHORTED TO GROUND









Measure the resistance between ground and the (V371/V71) and (V372/V72) S/C Switch Signal circuits at both Switch harness connectors.

Is the resistance below 100 ohms?

Yes

- Repair the short to ground in the (V371/V71) or (V372/V72) S/C Switch Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 12

12. SPEED CONTROL SWITCH VOLTAGE VALUES

Allow the engine to idle.

With a scan tool, monitor the S/C Switch voltage readings.





Take these same voltage measurements with a voltmeter by back probing the (V371) S/C Switch No.1 Signal circuit and the (V372) S/C Switch No.2 Signal circuit at the switches.

Compare the voltage readings on the voltmeter to what the scan tool displayed.

Are the voltage readings out of the listed specification and is there less than a 0.2 of a volt difference between the voltmeter switch values and the scan tool switch values?

Yes

- Replace the Speed Control Switch.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 13

13. PCM

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

Were there any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Replace and program the Powertrain Control Module.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
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