Pinpoint Test A: The Speed Control Is Inoperative

WARNING: This page is about a different car, the 2006 Mercury Milan, 2006 Lincoln Zephyr, and 2006 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

A1 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCs)
- Review the recorded DTCs from the PCM self-test.
- Are any non-speed control DTCs recorded?
Yes : REFER to the INTRODUCTION - GASOLINE article. REPAIR all PCM DTCs and RETEST the speed control.

No : GO to A2.
A2 CHECK THE STOPLAMP SWITCH
- Key in ON position.
- Enter the following diagnostic mode on the scan tool: PCM
- Stoplamp Switch PID.
- Monitor the PCM stoplamp switch PID.
- Apply and release the brake pedal.
- Does the PID value agree with the brake pedal position?
Yes : For automatic transaxle, GO to A4.

For manual transaxle, GO to A3.

No : GO to PINPOINT TEST B .
A3 CHECK THE CPP SWITCH
- Enter the following diagnostic mode on the scan tool: PCM CPP Switch PID.
- Monitor the PCM CPP switch PID.
- Apply and release the clutch pedal.
- Does the PID value agree with the clutch pedal position?
Yes : GO to A4.

No : GO to PINPOINT TEST D .

A4 CHECK THE SPEED CONTROL SWITCH

Key in OFF position.
Disconnect: PCM C175b.

Measure the resistance between the PCM C175b-56, circuit VES10 (WH), harness side and the PCM C175b-57, circuit RES08 (GN/BN), harness side while pressing the speed control switches as follows:

SPEED CONTROL SWITCH RESISTANCE VALUE CHART

Speed Control Switch	Resistance Value
OFF	Less than 5 ohms
SET-	298 - 304 ohms
SET +	596 - 608 ohms
RESUME	1,101 - 1,123 ohms
ON	2,091 - 2,133 ohms
No switch pressed	4,279 - 4,363 ohms

Fig 1: Checking Speed Control Switch

Courtesy of FORD MOTOR CO.

Are the speed control switch resistance values OK?

Yes : For automatic transaxle, GO to A5.

For : manual transaxle, GO to A6.

No : INSTALL a new speed control switch. REFER to SPEED CONTROL SWITCH . TEST the system for normal operation.

A5 CHECK THE DIGITAL TR SENSOR
- Connect: PCM C175b.
- Apply the parking brake.
- Key in ON position.
- Enter the following diagnostic mode on the scan tool: PCM TR Sensor PID.
- Monitor the PCM TR sensor PID.
- Select DRIVE.
- Does the PID value agree with the transmission range selector lever position?
Yes : GO to A6.

No : REFER to AUTOMATIC TRANSMISSION - 6 SPEED to diagnose the digital TR sensor.
A6 CHECK FOR ANTI-LOCK BRAKE SYSTEM (ABS) DTCs
- Check for any ABS DTCs.
- Are any ABS DTCs recorded?
Yes : REFER to VEHICLE DYNAMIC SYSTEMS .

No : GO to A7.
A7 CHECK THE SPEEDOMETER OPERATION
- Check the operation of the speedometer.
- Does the speedometer operate correctly?
Yes : GO to A8.

No : REFER to INSTRUMENT CLUSTER to continue diagnosis of the speedometer.
A8 CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Check for:
  - Corrosion
  - Pushed-out pins
- Connect all the PCM connectors and make sure they seat correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
Yes : INSTALL a new PCM. REFER to ELECTRONIC ENGINE CONTROLS - 2.3L or ELECTRONIC ENGINE CONTROLS - 3.0L (4V) . 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.