1994 PCED OBDI-A | SECTION 6A: EEC-IV Pinpoint Test
Procedures |
TB1 DIAGNOSTIC TROUBLE CODES (DTCS) 47, 633 AND 691
DTCs 47 and 633 indicate the 4x4 Low Selector Lever is not in the 4x2 or 4x4 high position (observed in Key On Engine Off (KOEO) Self-Test). A change in the automatic transmission shift cycle will occur.
DTC 691 4x4 selector fault (observed in Continuous Self-Test) is set when a stored Kam value for N/V (engine rpm/vehicle speed) is compared to a calculated N/V for the current switch position and driving condition. If these checks disagree, DTC 691 is set.
Possible Causes:
- Damaged 4x4 Low switch or 4x4 selector lever position.
- Shorted harness.
- Damaged PCM.
- Internal damage to transfer case.
Is the 4x4 lever positioned in 4x2/4x4 high?
| Yes | No |
|---|
| GO to TB4. | RERUN KOEO Self-Test with positioning selector in 4x2/4x4 high. |
TB2 DIAGNOSTIC TROUBLE CODES (DTCS) 65, 632 and 653
DTCs 65, 632 and 653 indicate the Transmission Control Switch (TCS) was not cycled between engine "ID Code" and the "Goose Test" in Key On Engine Running (KOER) Self-Test.
Possible Causes:
- TCS damaged or switch not cycled during self-test.
- Shorted harness.
- Damaged Powertrain Control Module (PCM).
- Open harness or fuse.
Was TCS cycled during KOER Self-Test?
| Yes | No |
|---|
| GO to TB4. | RERUN KOER Self-Test cycling the TCS. |
TB3 DIAGNOSTIC TROUBLE CODES (DTCS) 97, 623 AND 631
DTCs 97, 623 and 631 indicates a transmission control light circuit concern (observed during Key On Engine Off (KOEO) Self-Test).
Possible Causes:
- Burned out bulb.
- Shorted harness.
- Open harness/fuse.
Was the TCS cycled during KOEO Self-Test?
| Yes | No |
|---|
| GO to TB5. | RERUN KOEO Self-Test cycling the TCS. |
TB4 CYCLE THE APPROPRIATE CIRCUIT:
(4x4 LOW OR TRANSMISSION CONTROL)
- Key off.
- Disconnect Powertrain Control Module (PCM). Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary.
- Install breakout box, leave PCM disconnected.
- Key on, engine off.
- For 4x4 Low circuit:
- Measure voltage between Test Pin 12 and Test Pin 40/60 at the breakout box while moving the 4x4 select lever between 4x2 and 4x4 Low several times.
- For TCS circuit:
- Measure voltage between Test Pin 41 and Test Pin 40/60 at the breakout box while cycling the transmission control switch several times.
Does the voltage cycle?
| Yes | No |
|---|
| REPLACE PCM. REMOVE breakout box. RERUN Quick Test. | For a driveability symptom only:
GO to TB7.For a DTC:
GO to TB5. For 5.0L Mustang only:
GO to TB20. |
TB5 CHECK HARNESS CIRCUIT(S) FOR SHORT TO GROUND
- Key off.
- Breakout box installed, PCM disconnected.
- For 4x4 Low circuit:
- Disconnect 4x4 Low switch. Inspect both ends of the connector for damaged or pushed out pins, moisture, corrosion, loose wires, etc. Service as necessary.
- Measure resistance between Test Pin 12 and Test Pin 40/60 at the breakout box.
- For Transmission Control circuits:
- Disconnect Transmission Control Switch. Inspect both ends of the connector for damaged or pushed out pins, moisture, corrosion, loose wires, etc. Service as necessary.
- Measure resistance between Test Pin 41 and Test Pin 40/60 at the breakout box.
- Measure resistance between Test Pin 32 for E/F/B Series Trucks, Test Pin 14 for 3.2L SHO or Test Pin 55 for all others and Test Pin 40/60 at the breakout box.
Is each resistance greater than 10,000 ohms?
| Yes | No |
|---|
For original DTCs 47, 65, 632, 633, 653 and 691:
GO to TB8.For original DTCs 97, 623 and 631:
GO to TB6. | For original DTCs 47, 633 and 691:
SERVICE short circuit. RERUN Key On, Engine Off Self-Test.For original DTCs 65, 632 and 653:
SERVICE short circuit. RERUN Engine Running Self-Test. If DTC is still present, GO to TB7. For original DTCs 97, 623 and 631:
SERVICE short circuit. RERUN Key On, Engine Off Self-Test. |
TB6 CHECK KEYPOWER THROUGH TCIL CIRCUIT
- Key on, engine off.
- Breakout box installed, PCM disconnected.
- Measure voltage between Test Pin 32 for E/F/B Series Trucks, Test Pin 14 for 3.2L SHO or Test Pin 55 for all others and Test Pin 40/60 at the breakout box.
Is voltage greater than 10.5 volts?
| Yes | No |
|---|
| REPLACE PCM. REMOVE breakout box. RERUN Quick Test. | GO to TB7. |
TB7 CHECK OUTPUT DRIVER SIGNAL
Note: When entering this Test Step with a symptom or a Self-Test Pass code, first disconnect Powertrain Control Module (PCM). Inspect for damaged or pushed out pins, loose wires, etc. Service as necessary.
- Key off.
- Breakout box installed, PCM disconnected.
- Key on, engine off.
- For 4x4 Low circuit:
- Switch disconnected.
- Measure voltage between Test Pin 12 and PWR GND at the breakout box (ohmmeter negative probe).
- For TCIL circuit:
- Measure voltage between Test Pin 32 for E/F/B Series Trucks, Test Pin 14 for 3.2L SHO or Test Pin 55 for all others and PWR GND at the breakout box (ohmmeter negative probe).
Are both voltage readings at least 2.0 volts?
| Yes | No |
|---|
| GO to TB8. | INSPECT for damaged indicator bulb (4x4 Low LED or TCIL) or damaged fuse in fuse panel. If OK, SERVICE open circuit. REMOVE breakout box. RECONNECT all components. RERUN Quick Test. |
TB8 CHECK CONTINUITY OF THE 4x4 LOW OR TRANSMISSION CONTROL SWITCH HARNESS
- Key off.
- Breakout box connected, PCM disconnected.
- Appropriate switch disconnected.
- For 4x4 Low circuit:
- Measure the resistance between Test Pin 12 at the breakout box and 4x4 Low circuit at 4x4 Low switch touch drive module vehicle harness connector.
- For TCS/TCIL circuit:
- Measure the resistance between keypower at the fuse panel (fuses) (ohmmeter positive probe) and power side of transmission control switch vehicle harness connector (ohmmeter negative probe).
- Measure the resistance between Test Pin 41 at the breakout box and signal side of transmission control switch vehicle harness connector.
Are both resistances less than 5.0 ohms?
| Yes | No |
|---|
| GO to TB9. | SERVICE open circuit(s). REMOVE breakout box. RECONNECT all components. RERUN Quick Test. |
TB9 CHECK HARNESS CIRCUIT(S) FOR SHORTS TO POWER
- Key off.
- Breakout box installed, PCM disconnected.
- Appropriate switch disconnected.
- For 4x4 Low circuit:
- Measure resistance between Test Pin 12 and Test Pin 37/57 at the breakout box.
- For TCS/TCIL circuits:
- Measure resistance between Test Pin 41 and Test Pins 37/57 at the breakout box.
- Measure resistance between Test Pin 32 for E/F/B Series Trucks, Test Pin 14 for 3.2L SHO or Test Pin 55 for all others and Test Pins 37/57 at the breakout box.
Is each resistance greater than 10,000 ohms?
| Yes | No |
|---|
| REPLACE damaged switch, either 4x4L range switch or transmission control switch (TCS) due to DTC received. REMOVE breakout box. RECONNECT PCM. RERUN Quick Test. | SERVICE short circuit(s). REMOVE breakout box. RECONNECT all components. RERUN Quick Test. |
TB20 CHECK THE TRANSMISSION CONTROL SWITCH MODULE (TCSM)
Does the voltage cycle?
| Yes | No |
|---|
| SERVICE the open circuit from the TCSM connector to PCM. CHECK orange/black wire to Test Pin 41. CHECK black/white wire to Test Pin 40/60. RECONNECT PCM. RERUN Self-Test. Note: If voltage cycles and the TCIL does not, GO to TB25. | GO to TB21. |
TB21 CHECK WIRING OF THE TRANSMISSION CONTROL SWITCH MODULE (TCSM)
- Key off.
- Breakout box installed, PCM disconnected.
- TCSM connected.
- Measure the voltage supply to the TCSM between the red/light green (+) wire and the black/white (-) wire.
Is the voltage greater than 10.5V?
| Yes | No |
|---|
| GO to TB22. | SERVICE open circuit or fuse from the TCSM connector to the ignition switch. REMOVE breakout box. RECONNECT all components. RERUN Self-Test. |
TB22 CHECK TRANSMISSION CONTROL MODULE SWITCH INPUT FROM TRANSMISSION CONTROL SWITCH
- Key on, engine off.
- Breakout box installed, PCM disconnected.
- Measure the voltage between the tan/white wire and the black/white wire while cycling the TCS several times.
Does the voltage cycle?
| Yes | No |
|---|
| REPLACE TCSM. REMOVE breakout box. RECONNECT PCM. RERUN Quick Test. | CHECK TCS circuit. |
TB23 TRANSMISSION CONTROL INDICATOR LIGHT (TCIL) ALWAYS ON
- Key on, engine off.
- Cycle the Transmission Control Switch (TCS).
Does the TCIL turn on and off?
| Yes | No |
|---|
| Concern may be intermittent. CHECK pin fit, wire crimps, pushed out pins. | GO to TB24. |
TB24 TRANSMISSION CONTROL SWITCH MODULE SHORT CIRCUIT CHECK
- Key off.
- Locate and unplug TCSM.
- Key on, engine off.
Does the TCIL remain on?
| Yes | No |
|---|
| Short to ground is in the 911 circuit (W/LG). REPAIR short. RECONNECT all components. VERIFY TCIL turns on and off. | TCIL turns off when TCSM is disconnected. REPLACE TCSM. |
TB25 TRANSMISSION CONTROL INDICATOR LIGHT (TCIL) NEVER ON
- Verify over drive is functional.
- Run Key On Engine Running (KOER) Self-Test.
Is DTC 631 present?
TB26 CHECK FOR VOLTAGE AT FUSE PANEL
- Key on, engine off.
- Using the EVTM, locate the fuse that supplies 12V to the TCIL.
- DVOM connected, measure the voltage at both sides of the fuse.
Is the voltage greater than 10.5V?
| Yes | No |
|---|
| GO to TB27. | REPLACE fuse. RECHECK TCIL operation. |
TB27 CHECK WIRING FROM FUSE PANEL TO TCSM CONNECTOR
- Key off.
- Disconnect TCSM.
- Locate circuit (911) on the vehicle harness side of the TCSM connector and ground pin (911).
- Key on, engine off.
Does TCIL light?
| Yes | No |
|---|
| Concern may be intermittent. CHECK pin fit, wire crimps, pushed out pins. | CHECK bulb, if OK, open is in the wiring between the fuse panel and the TCSM connector. SERVICE open. |
TB: Introduction