1994 PCED OBDI-A
SECTION 6A: EEC-IV Pinpoint Test
Procedures

TD: Manual Lever Position (MLP) Sensor
  TD: Introduction  

 

TD1 KEY ON ENGINE OFF DIAGNOSTIC TROUBLE CODES (DTCS) 67/634, 522 AND 654:
CHECK MANUAL LEVER POSITION (MLP) SENSOR ALIGNMENT

Does the tool fit properly?
YesNo
REMOVE tool. GO to TD2.PLACE the transmission in NEUTRAL. LOOSEN the two MLP sensor mounting bolts. MOVE the sensor to allow insertion of the Transmission Range Sensor Tool in the appropriate slots. TIGHTEN the two mounting bolts to specification. REMOVE tool. VERIFY shift linkage adjustment. CLEAR Continuous Memory (REFER to Quick Test Appendix, Section 5A). RERUN Quick Test.
 

TD2 CHECK CONTINUITY OF MLP SENSOR HARNESS CIRCUITS

Is each resistance less than 5.0 ohms?
YesNo
GO to TD3.SERVICE open circuit(s). REMOVE breakout box. RECONNECT all components. RERUN Quick Test.
 

TD3 CHECK TR CIRCUIT FOR SHORT TO POWER AND GROUND

Is each resistance greater than 10,000 ohms?
YesNo
GO to TD4.SERVICE short circuit(s). REMOVE breakout box. RECONNECT all components. RERUN Self Test.
 

TD4 CHECK TR SENSOR RESISTANCE

Is each resistance within specification?
YesNo
REPLACE PCM. REMOVE breakout box. RERUN Self Test.REPLACE MLP sensor. REMOVE breakout box. RERUN Self Test.
 

TD9 TRANSMISSION REMAINS IN 3RD GEAR ONLY WITH SELECTOR IN "D" AND "OD"
PRELIMINARY CHECKS

Can the symptom be consistently reproduced?
YesNo
GO to TD11.GO to TD20 (intermittent concern).
 

TD10 DIAGNOSTIC TROUBLE CODE (DTC) 634:
CHECK SYMPTOM

With the gear selector in D and OD position, is transmission ALWAYS in 3rd gear?
YesNo
GO to TD11.If symptom is "Transmission stays in 3rd gear occasionally," GO to TD20. For all other symptoms, DISREGARD Continuous DTC 634. CLEAR Continuous Memory. RETURN to Section 2A to address symptom/other DTCs as necessary.
 

TD11 CHECK FOR IGN START/RUN CIRCUIT VOLTAGE AT TRANSMISSION

Is voltage greater than 10.5 volts?




YesNo
Key off. GO to TD12.SERVICE open circuit (verify condition of related fuse). RECONNECT transmission connector. RERUN Quick Test. RE-EVALUATE symptom.
 

TD12 CHECK FUNCTION OF THE TRANSMISSION RANGE SWITCHES

Do the Transmission Range switches check out OK?




YesNo
GO to TD13.GO to TD14.
 

TD13 CHECK TRANSMISSION SWITCH INPUT VOLTAGES AT BREAKOUT BOX

Do Transmission Range Switch voltages check out OK?
YesNo
GO to the Transmission Group in the Service Manual to check all other possible causes of the symptom. Also GO to Section 2A to check all other possible causes. If all checks are OK, REPLACE PCM.SERVICE faulty circuit.
—For circuit voltage always low (less than 0.5 volt) (except PNP Pin 30):
SERVICE open circuit.

—For circuit voltage always greater than 10.5 volts:
SERVICE short to power.

—For circuit voltage that "mirrors" that of another circuit:
SERVICE shorted circuits.
REMOVE breakout box. RECONNECT PCM.
RERUN Quick Test. RE-EVALUATE symptom.

 

TD14 CHECK ADJUSTMENT/EXTERNAL WIRING OF THE MANUAL LEVER POSITION SWITCH

Are the above checks OK?
YesNo
REPLACE Manual Lever Position switch. RECONNECT all components.
RERUN Quick Test. RE-EVALUATE symptom.
SERVICE as necessary. RECONNECT all components.
RERUN Quick Test. RE-EVALUATE symptom.
 

TD20 VISUALLY CHECK EEC-IV HARNESS BETWEEN EEC-IV AND TRANSMISSION

Do Transmission Range switch and shift solenoid wires appear OK?
YesNo
GO to TD21.SERVICE as necessary. RE-EVALUATE symptom.
 

TD21 CHECK HARNESS AND CONNECTORS FOR INTERMITTENT OPENS OR SHORTS

Is a fault indicated?
YesNo
ISOLATE fault and SERVICE as necessary. REMOVE breakout box. RECONNECT all components. RE-EVALUATE symptom.RETURN to Section 2A to address this or any other symptom.
 

TD22 ROAD TEST (ESCORT/TRACER ONLY)