Diagnostic Test
- 1) SPEED CONTROL SWITCH STATUS
Start the engine.
With a scan tool, monitor each which function for the Speed Control Switches.
Press and release each Speed Control Button.
- Resume/Accel
- Cancel
- Decel (Coast)
- On/Off
- Set
Does each switch function change status when pressing and then depressing each switch?
Yes
- Refer to INTERMITTENT CONDITION .
- Perform POWERTRAIN VERIFICATION TEST .
No
- Go To 2).
- 2) SPEED CONTROL SWITCHES
Turn the ignition off.
Remove 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 (V38) S/C Switch No.2 Signal and (V937) 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 (V37) S/C Switch No.1 Signal and (V937) 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 3).
No
- Replace the Speed Control Switch that had the incorrect resistance value.
- Perform POWERTRAIN VERIFICATION TEST .
- 3) (V38) S/C SWITCH NO.2 SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
Disconnect the C3 PCM harness connector.
Ignition on, engine not running.
Measure the voltage of the (V38) S/C Switch No.2 Signal circuit in the S/C Switch harness connector.
Is the voltage above 5.0 volts?
Yes
- Repair the short to battery voltage in the (V38) S/C Switch No.2 Signal circuit.
- Perform POWERTRAIN VERIFICATION TEST .
No
- Go To 4).
- 4) CLOCKSPRING
Courtesy of DAIMLERCHRYSLER CORP.
Turn the ignition off.
Disconnect the C1 and C3 Clockspring harness connectors per Service Information.
Measure the resistance of the (V38) S/C Switch No.2 Signal circuit between the C1 and C3 Clockspring harness connectors.
Measure the resistance of the (V937) Switch Return circuit between the C1 and C3 Clockspring harness connectors.
Is the resistance above 5.0 ohms?
Yes
- Replace the Clockspring per Service Information.
- Perform POWERTRAIN VERIFICATION TEST .
No
- Go To 5).NOTE: Connect the Clockspring harness connectors per Service Information before continuing.
- 5) (V38) S/C SWITCH NO.2 SIGNAL CIRCUIT OPEN
Turn the ignition off.
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 (V38) S/C Switch No.2 Signal circuit from both Speed Control harness connectors to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms for both measurements?
Yes
- Go To 6).
No
- Repair the open in the (V38) S/C Switch No.2 Signal circuit.
- Perform POWERTRAIN VERIFICATION TEST .
- 6) (V937) SWITCH RETURN OPEN
NOTE: The measurement must be taken from both Speed Control Switch harness connectors.
Measure the resistance of the (V937) Switch Return circuit from the Speed Control harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms for both measurement?
Yes
- Go To 7).
No
- Repair the open in the (V937) Switch Return circuit.
- Perform POWERTRAIN VERIFICATION TEST .
- 7) (V38) S/C SWITCH NO.2 SIGNAL CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and the (V38) S/C Switch No.2 Signal circuit in the Speed Control harness connector.
Is the resistance below 100 ohms?
Yes
- Repair the short to ground in the (V38) S/C Switch No.2 Signal circuit.
- Perform POWERTRAIN VERIFICATION TEST .
No
- Go To 8).
- 8) (V38) S/C SWITCH NO.2 SIGNAL CIRCUIT SHORTED TO THE (V937) SWITCH RETURN CIRCUIT
Courtesy of DAIMLERCHRYSLER CORP.
Measure the resistance between the (V38) S/C Switch No.2 Signal circuit and the (V937) Switch Return circuit in the Speed Control harness connector.
Is the resistance below 5.0 ohms?
Yes
- Repair the short between the (V38) S/C Switch No.2 Signal circuit and the (V937) Switch Return circuit.
- Perform POWERTRAIN VERIFICATION TEST .
No
- Go To 9).
- 9) SPEED CONTROL SWITCH VOLTAGE VALUES
Connect the C3 PCM harness connector and the S/C Switch harness connectors.
Allow the engine to idle.
With a scan tool, monitor the S/C Switch voltage readings.
SWITCH POSITION SWITCH No.1 VOLTAGE VALUE SWITCH No.2 VOLTAGE VALUE NO SWITCHES PRESSED 4.31 to 4.78 volts 4.31 to 4.78 volts ON/OFF PRESSED 0.59 and 1.13 volts 3.53 and 3.92 volts RES/ACCEL PRESSED 3.88 to 4.17 volts 2.04 to 2.47 volts SET PRESSED 3.16 to 3.56 volts 1.17 to 1.56 volts COAST PRESSED 2.57 to 2.94 volts 0.77 to 1.09 volts CANCEL PRESSED 1.59 to 1.99 volts 2.84 to 3.25 volts Take these same voltage measurements with a voltmeter by back probing the (V37) S/C Switch No.1 Signal circuit and the (V38) 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 POWERTRAIN VERIFICATION TEST .
No
- Go To 10).
- 10) 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 POWERTRAIN VERIFICATION TEST .
No
- Replace and program the Powertrain Control Module per Service Information.
- Perform POWERTRAIN VERIFICATION TEST .