Brake On/Off (BOO) Switch
The PCM receives a signal from the BOO switch when the brake switch is operated. Torque converter clutch is disengaged when brakes are applied. Faulty switch will affect torque converter operation.
Barometric Pressure (BARO) Sensor
The BARO sensor measures barometric pressure to determine altitude at which vehicle is operating. The PCM uses this to control line pressure. Sensor failure can cause firm shift feel and late shifts at altitude.
Camshaft Position (CMP) Sensor
The CMP sensor identifies when No. 1 piston is at TDC and sends a signal to the PCM.
Crankshaft Position (CKP) Sensor
The CKP sensor sends crankshaft rotation speed to the PCM.
Engine Coolant Temperature (ECT) Sensor
Engine temperature signal is sent to PCM. Malfunctioning ECT will affect torque converter clutch operation.
Pulse Signal Generator (PSG)
The PSG is a magnetic pickup that sends reverse clutch drum speed signal to the PCM. Malfunction of sensor may cause harsh engagements of shifts.
Throttle Position (TP) Sensor
The TP sensor is a potentiometer mounted to the engine throttle body. The PCM receives a signal from the TP sensor relaying throttle plate position. TP sensor failure will cause PCM to operate in fail safe mode and raise line pressure to prevent transaxle damage. This condition will result in harsh engagements, firm shift feel, abnormal shift schedule and TCC not engaging or cycling.
Transmission Control Switch (TCS)
Switch is mounted on shift lever handle. On/Off operation is displayed by Transmission Control Indicator Light (TCIL). TCIL will flash if EPC circuit is shorted, or monitored sensor or actuator fails. Switch controls operation of 4th gear. Malfunction of switch will cause lack of 4th gear disable function.
Transmission Range (TR) Switch
The PCM monitors a series of step down resistors in the TR switch that act as a voltage divider. The voltage signal corresponds with position of the transaxle range selector lever. The TR switch also contains the neutral/start and backup circuits. Malfunction of the TR switch may cause harsh engagements and firm shift feel. Improper shifting or shift selection and no engine cranking may also result.
Vehicle Speed Sensor (VSS)
The VSS is a magnetic pickup that sends vehicle speed signal to the PCM. Malfunction of sensor may cause harsh engagements of shifts.
Hard Failures
Hard failures cause Malfunction Indicator Light (MIL) to come on and trouble codes to be set in Powertrain Control Module (PCM) memory. Trouble code remains until problem is repaired. To retrieve trouble codes, see READING SELF-DIAGNOSTIC CODES . Use circuit tests to determine cause of malfunction.
If a sensor fails, PCM will use a substitute value in its calculations to continue engine operation. PCM can estimate failed sensor values based on feedback from working sensors. In this condition, known as Limited Operating Strategy (LOS), vehicle runs but driveability will not be optimum.
Intermittent Failures
Intermittent failures may cause Malfunction Indicator Light (MIL) to flicker or glow. Light will go out after intermittent fault goes away. These faults indicate that a defect may or may not be present at time of testing, however corresponding trouble code will be retained in PCM memory.
If related fault does not reoccur within a certain time frame, trouble code will be erased from PCM memory. Intermittent failures may be caused by a sensor, connector or wiring problems.
Visual Check & Vehicle Preparation
Before hooking up any equipment to diagnose EEC system, visually check following and perform preparation procedures
- Perform all necessary safety precautions to prevent personal injury or vehicle damage.
- Block drive wheels. Set parking brake. Place shift lever in "P" (Park). DO NOT move shift lever during test unless specifically directed to do so.
- Check condition of air cleaner and air ducting.
- Check all vacuum hoses for leaks, restrictions and proper routing.
- Check EEC system wiring harness connections for corrosion, damaged pins, loose wires and improper routing.
- Check PCM, sensors and actuators for physical damage.
- Check engine coolant and oil level.
- Check battery condition. Turn off all lights and accessories.
Ensure vehicle doors are closed when measuring voltage.
- Ensure engine is at operating temperature.
- Check exhaust system for leaks.
EQUIPMENT HOOKUP
Note. After performing equipment hookup, follow appropriate quick test procedures based on type of equipment being used. See QUICK TEST.
Analog Volt-Ohmmeter (VOM)
Turn ignition off. Locate Data Link Connector (DLC). see scheme 1and see scheme 2. Connect positive (+) lead of VOM to PCM STO terminal (Escort and Tracer) or TCM STO terminal (Probe) at DLC and negative test lead to engine ground (GND). (Scheme 59) Set VOM to 0-20V DC range. Connect a jumper wire between ground and PCM STI terminal (Escort and Tracer) or TCM STI terminal (Probe) of DLC.
Using Malfunction Indicator Light (MIL)
Check MIL operation. Turn ignition on. If MIL is on, MIL circuit is okay. Go to next step. If MIL is off, go to CIRCUIT TEST MIL. See appropriate TESTS W/CODES article in ENGINE PERFORMANCE section. After performing CIRCUIT TEST MIL, return to this procedure. Connect a jumper wire between ground and PCM STI terminal of DLC. see scheme 3
Overdrive Off Light (ODL)
Connect a jumper wire between ground and TCM STI terminal of DLC. see scheme 3
Super Star II Tester
- Turn ignition off. Connect color-coded adapter cable leads to Super Star II tester. Connect service adapter cables to vehicle Data Link Connector (DLC). see scheme 1and see scheme 2.
- Connect Super MECS Adapter (007-00049 or 007-00052) between adapter cables and vehicle DLC. Slide adapter switch to PCM position (Escort and Tracer) or TCM position (Probe). Slide Super Star II tester switch to EEC/MECS position.
New Generation Star Tester
- Turn ignition off. Connect power cable and data cable to scan tester. Connect Rotunda Super MECS Adapter (007-00052) to scan tester data cable.
- Plug matching connector on Super MECS adapter into vehicle DLC. see scheme 1through see scheme 3. Slide switch on Super MECS adapter to PCM position (Escort and Tracer) or TCM position (Probe). Plug power cable on scan tester into cigar lighter or use battery adapter.
Analog VOM
Watch voltmeter and count needle sweeps (between 0-12 volts) to determine code. Pay careful attention to length of pauses in order to read codes correctly. A 2-second pause occurs between digits in a code. A 4-second pause occurs between each code. (Scheme 59)
MIL/CHECK ENGINE Light
Service codes are displayed as flashes. Code flashes are read in the same manner as analog VOM.
Service codes are displayed as flashes. Code flashes are read in the same manner as analog VOM.
New Generation Star or Super Star II Scan Tester
Codes will be displayed digitally. KOEO codes include hard and intermittent failures. To determine failure type (hard or intermittent), record and clear codes stored in PCM/TCM memory. Operate vehicle, and repeat KOEO self-test. Codes that reappear immediately are hard failures. Codes that do not reappear are intermittent failures.
Repair hard failures in order of code appearance before performing KOER self-test. Use appropriate EEC CODE REFERENCE table to determine circuit test to perform. Clear codes from PCM memory after they have been recorded and/or faults have been repaired. See CLEARING CODES. When performing quick test, if no trouble codes are found during KOEO self-test, proceed to KOER self-test.
Reading Code Using Analog Volt-Ohmmeter (VOM) Courtesy of Ford Motor Co. Scheme 59
CLEARING CODES
| CAUTION | When battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in APPLICATIONS & IDENTIFICATION. |
To clear trouble codes, deactivate self-test by disconnecting jumper wire from PCM STI or TCM STI terminal at Data Link Connector (DLC). Disconnect negative (-) battery cable. Depress brake pedal for 5-10 seconds. All hard codes and intermittent codes will be erased from PCM/TCM memory.
ANALOG VOM, MIL OR ODL
Note. Reading codes using MIL or ODL pulses is similar to reading codes using VOM needle sweeps.
If codes are present, refer to EEC CODE REFERENCE table to determine circuit test to perform.
COMMUNICATION CODES
If scan tool will not communicate with PCM (no response) a communication error exists. A communication error could be caused by the following
- Operator error.
- Vehicle wiring.
- DLC terminals damaged.
- PCM malfunction.
- Low battery voltage.
The scan tool may display a 2-digit code indicating communication status. These codes are not DTCs. Some status code indicate normal communication function. See COMMUNICATION CODES table. If scan tool indicates a communications error (e.g., Code 10), go to CIRCUIT TEST QA under appropriate TESTS W/CODES article in ENGINE PERFORMANCE section.
| Code | Description | |
|---|---|---|
| Normal PCM Response | ||
| 00 | General Affirmative PCM Received A Valid Request From Scan Tool | |
| 61 | Normal Exit With Results PCM Completed A Valid Request (Test) A DTC Was Recorded | |
| 62 | Normal Exit, No Results PCM Completed A Valid Request (Test) No DTC Was Recorded | |
| Abnormal PCM Response | ||
| 10 | General Reject PCM Will Not Respond | |
| 11 | Mode Not Supported PCM Is Not Capable Of Performing A Requested Test | |
| 12 | Invalid Data Format An Unrecognized Character Is Inserted In to A String Of Data | |
| 21 | PCM Is Busy At Time Of Request PCM Is Already Performing A Test At Time Another Test Is Being Requested | |
| 22 | Entry Conditions Not Correct Usually Operator Error i.e. Engine Not Running, etc.) | |
| 23 | Results Not Done Request Received, But PCM Is Not Ready To Respond | |
| 50 | Upload Not Accepted Request Cannot Be Accomplished Due To Fault Condition | |
| 63 | Abnormal Exit With Results While Performing Test, Error Occurred, But PCM Has Results | |
| 64 | Abnormal Exit Without Results While Performing Test, Error Occurred, And No Results Are Available | |
COMMUNICATION CODES
EEC CODE REFERENCE TABLES
Note. In addition to transmission fault codes, engine-related fault codes may be output during QUICK TEST procedure. These fault codes pertain to engine performance and must be repaired first as engine performance will greatly affect transmission operation. For information and testing procedures of engine-related fault codes and components, see appropriate TESTS W/CODES article in ENGINE PERFORMANCE section.
| Fault Code (1) | Circuit Test | Code Definition |
|---|---|---|
| 02 | (2) | CKP Sensor |
| 03 | (2) | CMP Sensor |
| 06 | (2) | Vehicle Speed Sensor |
| 08 | (2) | Volume Airflow Sensor |
| 09 | (2) | ECT Sensor |
| 10 | (2) | IAT Sensor |
| 12 | (2) | TP Sensor |
| 14 | (2) | BARO Sensor |
| 15 | (2) | Heated Oxygen Sensor |
| 17 | (2) | Heated Oxygen Sensor |
| 25 | (2) | FPRC Solenoid |
| 26 | (2) | EVAP Canister Purge Solenoid |
| 34 | (2) | IAC Solenoid |
| 41 | (2) | HSIA Control Solenoid |
| 55 | PSG | Pulse Signal Generator |
| 56 | TFT | TFT Sensor |
| 60 | SCP | 1-2 Shift Solenoid |
| 61 | SCP | 2-3 Shift Solenoid |
| 62 | SCP | 3-4 Shift Solenoid |
| 63 | SCP | TCC Control Solenoid |
| (1) If Super Star II Tester displays STO LO or VOM displays zero volt, go to CIRCUIT TEST STI. See appropriate TESTS W/CODES article in ENGINE PERFORMANCE section. (2) See appropriate TESTS W/CODES article in ENGINE PERFORMANCE section. | ||
| (1) | If Super Star II Tester displays STO LO or VOM displays zero volt, go to CIRCUIT TEST STI. See appropriate TESTS W/CODES article in ENGINE PERFORMANCE section. |
| (2) | See appropriate TESTS W/CODES article in ENGINE PERFORMANCE section. |
EEC CODE REFERENCE (ESCORT & TRACER)
| Fault Code (1) | Circuit Test | Code Definition | |
|---|---|---|---|
| PCM Codes | |||
| 02 | (2) | CKP Sensor No. 2 | |
| 03 | (2) | CMP Sensor | |
| 04 | (2) | CKP Sensor No. 1 | |
| 05 | (2) | Knock Sensor | |
| 08 | (2) | Volume Airflow Sensor | |
| 09 | (2) | ECT Sensor | |
| 10 | (2) | IAT Sensor | |
| 12 | (2) | TP Sensor | |
| 14 | (2) | BARO Sensor | |
| 15 | (2) | Left Heated O2 Sensor | |
| 16 | (2) | EGR Position Sensor | |
| 17 | (2) | Left Heated O2 Sensor | |
| 23 | (2) | Right Heated O2 Sensor | |
| 24 | (2) | Right Heated O2 Sensor | |
| 25 | (2) | FPRC Solenoid | |
| 26 | (2) | EVAP Canister Purge Solenoid | |
| 28 | (2) | EGR Control Solenoid | |
| 29 | (2) | EGR Vent Solenoid | |
| 34 | (2) | IAC Solenoid | |
| 41 | (2) | VRIS Solenoid No. 1 | |
| 46 | (2) | VRIS Solenoid No. 2 | |
| 67 | (2) | Low Fan Control Relay | |
| TCM Codes | |||
| 01 | (2) | CKP Sensor No. 1 | |
| 06 | (2) | Vehicle Speed Sensor | |
| 12 | (2) | TP Sensor | |
| 14 | (2) | BARO Sensor | |
| 55 | PSG | Pulse Signal Generator | |
| 56 | TFT | TFT Sensor | |
| 57 | RTS1 | Reduce Torque Signal No. 1 | |
| 58 | RTS2 | Reduce Torque Signal No. 2 | |
| 59 | TRS | Torque Reduce ECT Signal | |
| 60 | SCP | 1-2 Shift Solenoid | |
| 61 | SCP | 2-3 Shift Solenoid | |
| 62 | SCP | 3-4 Shift Solenoid | |
| 63 | SCP | TCC Control Solenoid | |
| 64 | SCP | Downshift Solenoid | |
| 65 | DCS | TCC Solenoid | |
| 66 | DCS | Line Pressure Solenoid | |
| (1) If Super Star II Tester displays STO LO or VOM displays zero volt, go to CIRCUIT TEST STI. See appropriate TESTS W/CODES article in ENGINE PERFORMANCE section. (2) See appropriate TESTS W/CODES article in ENGINE PERFORMANCE section. | |||
| (1) | If Super Star II Tester displays STO LO or VOM displays zero volt, go to CIRCUIT TEST STI. See appropriate TESTS W/CODES article in ENGINE PERFORMANCE section. |
| (2) | See appropriate TESTS W/CODES article in ENGINE PERFORMANCE section. |
EEC CODE REFERENCE (PROBE)
HOW TO USE CIRCUIT TESTS
- DO NOT perform any circuit test unless specifically instructed by a procedure under QUICK TEST. Ensure all non-EEC related faults are corrected. Follow each test step in order until fault is found. When more than one code is received, start with first code displayed.
- Use circuit tests to check electrical circuits before replacing sensors or any other components. Always test circuits for continuity between sensor and PCM. Test all circuits for short to power, opens or short to ground.
- DO NOT connect any test light or measure voltage or resistance at PCM unless specified in testing procedure. DO NOT pierce wiring. If backprobing is specified, always backprobe harness side of connector. DO NOT probe connector side.
- Isolate both ends of circuit and turn ignition off whenever checking for shorts or continuity, unless specified otherwise. Disconnect solenoids and switches before checking circuit continuity or energizing solenoids.
EEC CIRCUIT TESTS - ESCORT & TRACER 1.8L, PROBE 2.5L
Note. Procedures in CIRCUIT TESTS are written for the use of the following Ford Motor Co. test equipment
- Super Star II Tester (007-0041B) or New Generation Star (NGS) Tester (007-00500)
- 60-Pin Breakout Box (007-00033)
- 1.8L Breakout Box Adapter (T96P-12A650-B)
- 2.5L Breakout Box Adapter (T96P-12A650-C)
- Transmission Tester (007-0037B) with appropriate overlays.
Terminal pin references are based on this equipment and appropriate overlays. All references to "test pins", "test terminals" or "jacks" refer to test equipment. When aftermarket test equipment is used, always follow test equipment manufacturers procedures.