Pinpoint Test A: The Speed Control Is Inoperative - Gasoline Vehicles

WARNING: This page is about a different car, the 2006 Ford Pickup, 2006 Ford F550 Super Duty, 2006 Ford F450 Super Duty, and 2006 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

A1 CHECK FOR DTCs
- Review the recorded DTCs from the PCM self-test.
- Are any DTCs recorded?
Yes : REFER to the POWERTRAIN CONTROL MODULE (PCM) DIAGNOSTIC TROUBLE CODE (DTC) INDEX .

No : Go to A2.

A2 CHECK THE SPEED CONTROL SWITCH

Disconnect: PCM C175b.
Measure the resistance between the PCM C175b-19, circuit 151 (LB/BK), harness side and the PCM C175b-30, circuit 133 (BK), harness side.

SPEED CONTROL SWITCH - RESISTANCE SPECIFICATIONS

Speed Control Switch	Resistance Value
OFF	Less than 5 ohms
SET-	285-315 ohms
SET +	570 - 630 ohms
RESUME	1,055 - 1,165 ohms
ON	2,004 - 2,216 ohms
No switch pressed	4,094 - 4,526 ohms

Fig 1: Checking Speed Control Switch

Courtesy of FORD MOTOR CO.

Are the speed control switch resistance values OK?

Yes : If equipped with an automatic transmission, Go to If equipped with a manual transmission, Go to A3.

No : INSTALL a new speed control switch. REFER to SPEED CONTROL SWITCH . CLEAR the DTCs. REPEAT the self-test.

A3 CHECK THE DIGITAL TR SENSOR
- Connect: PCM C175b.
- Key in ON position.
- Enter the following diagnostic mode on the scan tool: PCM PID Data Monitor and Record.
- Monitor the PCM TR sensor PID.
- Select DRIVE.
- Does the PID value agree with the transmission range selector lever position?
Yes : Go to A4.

No : REFER to AUTOMATIC TRANSAXLE/TRANSMISSION - TORQSHIFT to diagnose the TR sensor.
A4 CHECK THE DIGITAL TR SENSOR FOR CORRECT ALIGNMENT
- Check the digital TR sensor alignment. Refer to AUTOMATIC TRANSAXLE/TRANSMISSION - TORQSHIFT .
- Is the digital TR sensor aligned correctly?
Yes : Go to A8.

No : ADJUST the digital TR sensor. REFER to AUTOMATIC TRANSAXLE/TRANSMISSION - TORQSHIFT . TEST the system for normal operation.
A5 CHECK THE CPP SWITCH
- While pressing and releasing the clutch pedal, measure the resistance between the PCM C175b-32, circuit 306 (TN/LB), harness side and ground.
  
  Fig 2: Checking CPP Switch
  Courtesy of FORD MOTOR CO.
- Is the resistance greater than 10,000 ohms with the clutch pedal pressed, and less than 5 ohms with the clutch pedal released?
Yes : Go to A8.

No : Go to A6.
A6 CHECK CIRCUIT 306 (TN/LB) FOR AN OPEN
- Disconnect: CPP Switch C257.
- Measure the resistance between the PCM C175b-32, circuit 306 (TN/LB), harness side and the CPP switch C257-4, circuit 306 (TN/LB), harness side.
  
  Fig 3: Checking Circuit 306 (TN/LB) For Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
Yes : Go to A7.

No : REPAIR the circuit. TEST the system for normal operation.
A7 CHECK CIRCUIT 570 (BK/WH) FOR AN OPEN
- Measure the resistance between the CPP switch C257-3, circuit 570 (BK/WH), harness side and ground.
  
  Fig 4: Checking Circuit 570 (BK/WH) For Open
  Courtesy of FORD MOTOR CO.
- Is the resistance less than 5 ohms?
Yes : INSTALL a new CPP switch. TEST the system for normal operation.

No : REPAIR the circuit. TEST the system for normal operation.
A8 CHECK THE PARKING BRAKE WARNING INDICATOR
- Key in ON position.
- While observing the parking brake warning indicator, apply and release the parking brake.
- Does the parking brake warning indicator operate correctly?
Yes : Go to A9.

No : REFER to INSTRUMENT CLUSTER to diagnose the parking brake warning indicator.
A9 CHECK THE VEHICLE SPEED
NOTE: This step may require an assistant.
- Enter the following diagnostic mode on the scan tool: Anti-Lock Brake System (ABS) Wheel Speed PID.
- Monitor and record the ABS module wheel speed PID while driving the vehicle at 48 km/h (30 mph) as indicated on the speedometer.
- Enter the following diagnostic mode on the scan tool: PCM Vehicle Speed PID.
- Monitor and record the PCM vehicle speed 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 vehicle speed PID?
Yes : Go to A10.

No : REFER to the INTRODUCTION - GASOLINE article to diagnose the output shaft sensor (OSS) signal.
A10 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 are seated 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 - GASOLINE ENGINES . CLEAR the DTCs. REPEAT the self-test.

No : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.