Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 14 other vehicles, including the 1996 Ford RV Cutaway, 1996 Ford Pickup, 1996 Ford F-Super Duty, 1996 Ford Econoline, and 1996 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

1)

Step 1) DTC 1780: Check Parameter Identification (PID) This DTC indicates TCS was not cycled during KOER SWITCH SELF-TEST . Possible causes for this DTC are:
- TCS failure.
- TCS circuitry.
- TCS operation omitted during KOER SWITCH SELF-TEST.
- Faulty Powertrain Control Module (PCM).
Turn ignition on. Connect New Generation Star (NGS) scan tool. On 1995 models, access CPP PID from PID/DATA MONITOR & RECORD menu. CPP represents TCS on scan tool. On 1996 models, access TCS PID from PID/DATA MONITOR & RECORD menu. On all models, observe PID reading and cycle TCS. TCS is located on end of shift lever. If PID reading indicates OFF (12 volts) with TCS depressed and ON (zero volts) with TCS released, TCS is okay. Go to step 15). If PID reading does not indicate OFF (12 volts) with TCS depressed and ON (zero volts) with TCS released, go to next step.

2) Check PID Reading For OFF Only

Ensure ignition is on. Cycle TCS. If PID reading indicates OFF only, go to next step. If PID reading does not indicate OFF only, go to step 5).

3) Check For TCS Failed Closed

Ensure ignition is on. Disconnect TCS connector. If PID reading does not indicate ON only, go to next step. If PID reading indicates ON only, replace TCS/TCIL. Confirm repair using scan tool and monitoring CPP or TCS PID from PID/DATA MONITOR & RECORD menu while operating TCS switch. Repeat QUICK TEST .

4) Check Tan/White Wire For Short To Battery Power

Turn ignition off. Disconnect PCM 104-pin connector. Turn ignition on. Measure voltage between ground and Tan/White wire at TCS wiring harness connector. If battery voltage is present, locate and repair short to power in Tan/White wire. Confirm repair using scan tool and monitoring CPP or TCS PID from PID/DATA MONITOR & RECORD menu while operating TCS switch. Repeat QUICK TEST . If battery voltage is not present, inspect PCM connector for damaged pins, corrosion and loose wires. Repair as necessary. Reconnect all connectors and go to step 12).

5) Check CPP PID For Open

If PID reading indicates ON only, go to next step. If PID reading does not indicate ON only, fault may be intermittent. Go to step 13).

6) Check Fuse

On Econoline, remove and inspect fuse No. 18 (15-amp) located in instrument panel fuse block. On Pickup, remove and inspect fuse No. 17 (10-amp) located in instrument panel fuse block. On all models, if fuse is blown, go to next step. If fuse okay, go to step 9).

7) Check For Short To Ground

Disconnect TCS connector. Measure resistance between ground and Red/Yellow wire at TCS wiring harness connector. If resistance is less than 5 ohms, locate and repair short to ground. Confirm repair using scan tool and monitoring CPP or TCS PID from PID/DATA MONITOR & RECORD menu while operating TCS switch. Repeat QUICK TEST . If resistance is 5 ohms or more, go to next step.

8) Check Tan/White Wire For Short To Ground

Disconnect PCM 104-pin connector. Turn ignition on. Measure resistance between ground and Tan/White wire at TCS wiring harness connector. If resistance is less than 5 ohms, locate and repair short to ground in Tan/White wire. Confirm repair using scan tool and monitoring CPP or TCS PID from PID/DATA MONITOR & RECORD menu while operating TCS switch. Repeat QUICK TEST . If resistance is 5 ohms or more, inspect for damaged pins, corrosion and loose wires. Repair as necessary. Reconnect all connectors and go to step 12).

9) Check For Open Circuit

Remove fuse No. 17 from instrument panel fuse block. Disconnect TCS connector. Turn ignition on. Measure voltage of Red/Yellow wire between non-powered side of fuse No. 18 (Econoline), or fuse No. 17 (Pickup) holder and TCS wiring harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, locate and repair open circuit between fuse holder and TCS connector. Confirm repair using scan tool and monitoring CPP or TCS PID from PID/DATA MONITOR & RECORD menu while operating TCS switch. Repeat QUICK TEST .

10) Check TCS

Connect a jumper wire between Tan/White wire and Red/Yellow wire at TCS wiring harness connector. Using scan tool, access CPP PID (1995 models) or TCS PID (1996 models) from PID/DATA MONITOR & RECORD menu. If PID reading indicates OFF, replace TCS/TCIL. Confirm repair using scan tool and monitoring CPP or TCS PID from PID/DATA MONITOR & RECORD menu while operating TCS switch. Repeat QUICK TEST . If PID reading does not indicated OFF, go to next step.

11) Check Tan/White Wire For Open

Turn ignition off. Ensure TCS is disconnected. Disconnect PCM 104-pin connector, and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Turn ignition on. Measure voltage between Tan/White wire at TCS wiring harness connector and test pin No. 29 at breakout box. If resistance is less than 5 ohms, reconnect all connectors and go to next step. If resistance is 5 ohms or more, locate and repair open circuit in Tan/White wire. Confirm repair using scan tool and monitoring CPP or TCS PID from PID/DATA MONITOR & RECORD menu while operating TCS switch. Repeat QUICK TEST .

12) Confirm PCM Fault

Turn ignition on. Using scan tool, access CPP PID (1995 models) or TCS PID (1996 models) from PID/DATA MONITOR & RECORD menu. If PID reading switches ON and OFF, no problem is indicated at this time. If PID reading does not switch ON and OFF, replace PCM. Confirm repair using scan tool and monitoring CPP or TCS PID from PID/DATA MONITOR & RECORD menu while operating TCS switch. Repeat QUICK TEST .

13) Check For Intermittent Open Or Short Circuit

Ensure jumper wire is connected between Red/Yellow wire at TCS wiring harness connector. Using scan tool, access CPP PID (1995 models) or TCS PID (1996 models) from PID/DATA MONITOR & RECORD menu. PID reading should indicate OFF. While observing PID, wiggle and bend small sections of wiring harness starting at TCS connector and working toward PCM. If a fault occurs, PID reading will switch between OFF and ON. If fault occurs, locate and repair intermittent in wiring harness. Confirm repair using scan tool and monitoring CPP or TCS PID from PID/DATA MONITOR & RECORD menu while operating TCS switch. Repeat QUICK TEST . If no fault occurs, go to next step.

14) Check For Intermittent Short To Power

Remove fuse No. 17 from instrument panel fuse block. Ensure jumper wire is connected between Tan/White wire and Red/Yellow wire at TCS wiring harness connector. Using scan tool, access CPP PID (1995 models) or TCS PID (1996 models) from PID/DATA MONITOR & RECORD menu. PID reading should indicate ON. While observing PID, wiggle and bend small sections of wiring harness starting at TCS connector and working toward PCM. If a fault occurs, PID reading will switch to OFF. If fault occurs, locate and repair intermittent in wiring harness. Confirm repair using scan tool and monitoring CPP or TCS PID from PID/DATA MONITOR & RECORD menu while operating TCS switch. Repeat QUICK TEST . If no fault occurs, no problem indicated at this time. Confirm repair using scan tool and monitoring CPP or TCS PID from PID/DATA MONITOR & RECORD menu while operating TCS switch. Repeat QUICK TEST .

15) DTC 1779: Check Transmission Control Indicator Light (TCIL)

This DTC indicates PCM has detected a TCIL circuit malfunction. Turn ignition on. Cycle Transmission Control Switch (TCS) several times. If TCIL turns off and on, no problem is indicated at this time. If TCIL does not turn off and on, go to next step.

16) Check Circuit No. 911 For Short To Power

Disconnect TCS connector. Measure voltage between ground and White/Light Green wire at TCS wiring harness connector. If battery voltage is present, go to next step. If battery voltage is not present, go to step 18).

17) Check PCM For Short To Power

Disconnect PCM 104-pin connector. Measure voltage between ground and White/Light Green wire at TCS wiring harness connector. If battery voltage is present, locate and repair short to power in White/Light Green wire. Recheck TCIL operation. If battery voltage is not present, inspect PCM connector for damaged pins, corrosion and loose wires. Repair as necessary. Reconnect all connectors and go to step 21).

18) Check For Fault

Disconnect TCS connector. Turn ignition on. Connect DVOM between ground and White/Light Green wire at TCS wiring harness connector. Using New Generation Star (NGS) tester, perform Output State Test. See ADDITIONAL SYSTEM FUNCTIONS . If voltage does not toggle between 12 volts and zero volts, go to next step. If voltage toggles between 12 volts and zero volts, replace TCS/TCIL. Recheck TCIL operation.

19) Check White/Light Green Wire For Short To Ground

Turn ignition off. Disconnect PCM 104-pin wiring harness connector. Turn ignition on. Measure resistance between ground and White/Light Green wire at TCS wiring harness connector. If resistance is more than 10 k/ohms, go to next step. If resistance is 10 k/ohms or less, locate and repair short to ground in White/Light Green wire. Recheck TCIL operation.

20) Check White/Light Green Wire For Open Circuit

Turn ignition off. Inspect PCM 104-pin connector for damaged pins, corrosion and loose wires. Repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between White/Light Green wire at TCS wiring harness connector and test pin No. 79 at breakout box. If resistance is less than 5 ohms, reconnect all connectors and go to next step. If resistance is 5 ohms or more, locate and repair open circuit in White/Light Green wire. Recheck TCIL operation.

21) Confirm PCM Fault

Turn ignition on. Cycle TCS switch several times. If TCIL turns OFF and ON, no problem is indicated at this time. If TCIL does not turn OFF and ON, replace PCM. Recheck TCIL operation.