Diagnostic Aids

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

Perform this test when instructed during QUICK TEST or if directed by other test procedures. This test is used to diagnose the following:

Wiring harness circuits (CCS, EPC, SS1, SS2, SS3, TCC and VPWR).
Faulty Powertrain Control Module (PCM).

Fig 1: Transmission Circuit & Connector Terminal ID (Ranger)

Fig 2: Transmission Circuit & Connector Terminal ID (Windstar)

TRANSMISSION SOLENOID IDENTIFICATION

Solenoid	Test Pin	KOEO Code
CCS	28	P1754
EPC	81	P1746 & P1747
SS1	27	P0750, P0751 & P1751
SS2	1	P0755, P0756, & P1756
SS3	53	P0760, P0761 & P1761
TCC	82	P0741, P0743, P1741, P1742, P1743 & P1744

1) DTC P0731/P0781, P0732/P0782, P0733/P0783, P0734/P0784, P0750, P0751, P0755, P0756, P0760, P0761, P1751, P1756 & P1761 - These codes indicate transmission mechanical failure or electrical malfunction. Probable causes are as follows:

Internal transmission damage.
Shift solenoid damage.
Shift solenoid circuit damage.
Faulty Powertrain Control Module (PCM).

Turn ignition off. Disconnect transmission wiring harness connector. Using a mirror, inspect connector terminals for damage, corrosion, loose wires or pushed out pins. Repair if necessary. Connect DVOM between VPWR terminal and suspect shift solenoid terminal at transmission wiring harness connector. Repeat KOEO self-test. If DVOM voltage reading cycles, fault is internal transmission damage. If DVOM voltage reading does not cycle, go to next step.

2) Check VPWR Circuit At Solenoid

Leave transmission wiring harness connector disconnected. Turn ignition off. Disconnect PCM 104-pin connector. Inspect pins for damage and repair if necessary. Install EEC-V Breakout Box (014-00950), leaving PCM disconnected. Turn ignition on. Measure voltage between test pins No. 71 and 97 (VPWR) at breakout box and chassis ground. If voltage is 10.5 volts or more, go to next step. If voltage is less than 10.5 volts, repair open in VPWR circuit. Clear PCM memory and repeat QUICK TEST.

3) Leave transmission wiring harness connector disconnected. Turn ignition off. Measure and record resistance between VPWR terminal of transmission wiring harness connector and test pins No. 71 and 97 (VPWR) at breakout box. Measure and record resistance between suspect solenoid terminal of transmission wiring harness connector and suspect solenoid terminal at breakout box. If each resistance measurement is less than 5 ohms, go to next step. If any resistance measurement is 5 ohms or more, repair open circuit and repeat QUICK TEST.

4) Leave ignition off and transmission wiring harness connector disconnected. Measure and record resistance between suspect solenoid terminal of transmission wiring harness connector and test pins No. 51, 76 and 91 at breakout box. Measure and record resistance between suspect solenoid terminal of transmission wiring harness connector and test pins No. 71 and 97 (VPWR) at breakout box. If any resistance measurement is less than 10,000 ohms, repair short circuit and repeat QUICK TEST. If all resistance measurements are 10,000 ohms or more, fault is internal transmission damage.

5) DTC P0741, P0743, P0746, P1746, P1747, P1749 & P1754

These codes indicate transmission electrical malfunction. Probable causes are as follows:

Internal transmission damage.
Shift solenoid damage.
Shift solenoid circuit damage.
Faulty Powertrain Control Module (PCM).

Turn ignition off. Disconnect transmission wiring harness connector. Using a mirror, inspect connector terminals for damage, corrosion, loose wires or pushed out pins. Repair if necessary. Connect DVOM between VPWR terminal and suspect shift solenoid terminal at transmission wiring harness connector. Connect scan tester to Data Link Connector (DLC). Using scan tester, activate scan tester Output Test Mode. Cycle suspect solenoid on and off. If DVOM voltage reading cycles, fault is inside transmission. Circuit testing is complete. If DVOM voltage reading does not cycle, go to next step.

6) Check VPWR Circuit At Solenoid

7) Leave transmission wiring harness connector disconnected. Turn ignition off. Disconnect scan tester. Measure and record resistance between VPWR terminal of transmission wiring harness connector and test pins No. 71 and 97 (VPWR) at breakout box. Measure and record resistance between suspect solenoid terminal of transmission wiring harness connector and suspect solenoid terminal at breakout box. If each resistance measurement is less than 5 ohms, go to next step. If any resistance measurement is 5 ohms or more, repair open circuit and repeat QUICK TEST.

8) Leave ignition off and transmission wiring harness connector disconnected. Measure and record resistance between suspect solenoid terminal of transmission wiring harness connector and test pins No. 51, 76 and 91 at breakout box. Measure and record resistance between suspect solenoid terminal of transmission wiring harness connector and test pins No. 71 and 97 (VPWR) at breakout box. If any resistance measurement is less than 10,000 ohms, repair short circuit and repeat QUICK TEST. If all resistance measurements are 10,000 ohms or more, fault is internal transmission damage.