Pinpoint Test A: The Speed Control Is Inoperative

WARNING: This page is about a different car, the 2007 Lincoln MKX and 2007 Ford Edge. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

A1 VERIFY POWERTRAIN CONTROL MODULE (PCM) CONFIGURATION
- Enter the following diagnostic mode on the diagnostic tool: Programmable Parameters
- Verify that the speed control is enabled in the PCM.
- Is the speed control enabled?
1. YES : Go to A2.
2. NO : ENABLE the speed control in the PCM using the scan tool programmable parameters menu. If no parameter exists, REFER to MODULE CONFIGURATION to carry out PCM programmable module installation (PMI). TEST the system for normal operation.
A2 CHECK FOR DTCs
- Review the recorded DTCs from the PCM self-test.
- Are any DTCs recorded?
1. YES : REFER to the PCM DTC Chart for correct diagnosis.
2. NO : Go to A3.
A3 CHECK THE STOPLAMP SWITCH
- Key in ON position.
- Enter the following diagnostic mode on the diagnostic tool: PCM Stoplamp Switch PID
- Monitor the PCM BOO PID.
- Apply and release the brake pedal.
- Does the PID value agree with the brake pedal position?
1. YES : Go to A4.
2. NO : Go to Pinpoint Test B .

A4 CHECK THE SPEED CONTROL SWITCH

Key in OFF position.
Disconnect: PCM C175b

Fig 1: Measuring Resistance Between PCM C175B-56 & C175B-57, Circuit VES10 (WH) & RES08 (GN/BN)

Courtesy of FORD MOTOR CO.

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
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

Are the speed control switch resistance values OK?

YES : Go to A5 .
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 diagnostic tool: PCM TR Sensor PID
- Monitor the PCM TR PID.
- Select DRIVE.
- Does the PID value agree with the transmission range selector lever position?
1. YES : Go to A6.
2. NO : REFER to AUTOMATIC TRANSAXLE/TRANSMISSION - 6F50 to diagnose the digital TR sensor.
A6 CHECK THE DIGITAL TR SENSOR FOR CORRECT ALIGNMENT
- Check the digital TR sensor alignment. Refer to AUTOMATIC TRANSAXLE/TRANSMISSION - 6F50 .
- Is the digital TR sensor aligned correctly?
1. YES : Go to A7.
2. NO : ADJUST the digital TR sensor. REFER to AUTOMATIC TRANSAXLE/TRANSMISSION - 6F50 . TEST the system for normal operation.
A7 CHECK THE VEHICLE SPEED
NOTE: This step may require an assistant.
- Enter the following diagnostic mode on the diagnostic tool: ABS Wheel Speed PID
- Monitor and record the ABS LF_WSPD PID while driving the vehicle at 48 km/h (30 mph) as indicated on the speedometer.
- Enter the following diagnostic mode on the diagnostic tool: PCM Vehicle Speed PID
- Monitor and record the PCM VSS PID while driving the vehicle at 48 km/h (30 mph).
- Does the speed indicated by the ABS module wheel speed PID match the PCM VSS PID?
1. YES : Go to A8.
2. NO : REFER to the Introduction - Gasoline Engines to diagnose the output shaft speed (OSS) sensor signal.
A8 CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Check for:
  - corrosion
  - damaged pins
  - 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?
1. YES : INSTALL a new PCM. REFER to ELECTRONIC ENGINE CONTROLS . TEST the system for normal operation.
2. NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.