Preliminary Instructions (M/T)

WARNING: This page is about a different car, the 1995 Ford Explorer and 1995 Ford Aerostar. However, it is still accessible from the selected car via links, so may be relevant.

Record and clear continuous memory codes. Warm engine to normal operating temperature. Accelerate moderately to 40 MPH. Start in first gear, shifting no higher than second gear. Coast down to idle, and stop. Shut off engine. Perform KOEO SELF-TEST, and record continuous memory codes. Go to step 1).

1) Continuous Memory Code 452 Code 452 indicates PCM detected incorrect output from VSS sometime during vehicle operation. Possible causes for this code are:

Faulty VSS.
Open or shorted circuit.
Faulty PCM.

Perform appropriate drive cycle procedure. See PRELIMINARY INSTRUCTIONS (A/T) or PRELIMINARY INSTRUCTIONS (M/T). Ensure driveability complaint can be verified. If Code 452 is still present or driveability complaint can be verified, go to next step. If code is not present or complaint cannot be verified, fault cannot be duplicated at this time. Clear codes, and see SYMPTOMS in appropriate TESTS W/O CODES (EEC-IV) article in the ENGINE PERFORMANCE section.

TESTS W/O CODES - EEC-IV (for Aerostar)
TESTS W/O CODES - EEC-IV (for Explorer)

2) Check Vehicle Speed Sensor (VSS) Circuit Continuity Turn ignition off. Disconnect VSS. Remove PCM 60-pin connector. Inspect terminals and repair if damaged. Install EEC-IV Breakout Box (T83L-50-EEC-IV). Measure resistance between VSS (+) terminal at VSS wiring harness connector and test pin No. 3 at breakout box. Measure resistance between VSS (-) terminal at VSS wiring harness connector and test pin No. 6 at breakout box. If any resistance reading is more than 5 ohms, service open circuit in VSS wiring harness and repeat step 1). If both resistance readings are 5 ohms or less, go to next step.

3) Check VSS Circuits For Short To Power Or Ground Turn ignition off. Ensure PCM and VSS are disconnected. Measure resistance between test pin No. 3 and test pins No. 6, 37 and 40 at breakout box. If any reading is less than 500 ohms, repair shorted VSS wiring harness and repeat step 1). If all readings are more than 500 ohms, go to next step.

4) Check VSS Resistance Leave ignition off. Disconnect VSS wiring harness connector. Measure resistance across VSS terminals. If reading is not 190-250 ohms, replace VSS and repeat step 1). If resistance is 190-250 ohms, replace PCM and repeat step 1).