Engine Controls - Basic Testing: Diagnosis Ford Aerostar I

VISUAL INSPECTION

Visually inspect all electrical wiring. Look for chafed, stretched, cut or pinched wiring. Ensure electrical connectors fit tightly and are not corroded. Ensure vacuum hoses are properly routed and are not pinched or cut. If necessary, see VACUUM DIAGRAMS article in the ENGINE PERFORMANCE Section to verify routing and connections. Inspect air induction system for possible vacuum leaks.

NO-START DIAGNOSIS

Note. For diesel information, see H - DSL TESTS W/O CODES article in the ENGINE PERFORMANCE Section.

Definition - No-start is defined as engine cranks okay, but does not start. Engine may fire a few times.

TEST 1, CHECK ECA FOR FAULT CODES

Repair any fault codes as necessary. See G - TEST W/ CODES article in the ENGINE PERFORMANCE Section. If no fault codes are retrieved, proceed to next test.

TEST 2, CHECK FOR SPARK DURING CRANK

Using Neon Bulb Spark Tester (D89P-6666-A), check for spark at each right side spark plug wire while cranking. If spark is present and consistent (one spark per crank revolution) on all right side spark plug wires, go to next test. If spark is not present or is inconsistent, go to TEST 5.

TEST 3, CHECK DIS MODULE PIP OUT

Install DIS diagnostic Cable (007-00044). Connect diagnostic cable to Breakout Box (T83L-50-EEC-IV). (Scheme 98) Use 2.3L overlay. Connect LED test light between breakout box pins No. (+) J31 (PIP EEC) and (-) J60 (BAT -). Crank engine. If test light blinks continuously during cranking, go to next test. If test light does not blink continuously during cranking, replace DIS module, and check for fault codes.

Scheme 98

TEST 4, CHECK PIP OUT CONTINUITY

With key off, disconnect ECA. Using ohmmeter, measure resistance between vehicle harness connector pin No. 56 and breakout box pin No. J31 (PIP EEC). (Scheme 99) If resistance is less than 5 ohms, see CIRCUIT TEST A in TESTS W/CODES article in the ENGINE PERFORMANCE Section. If resistance is more than 5 ohms, repair open circuit, reconnect ECA and retest system. If vehicle still does not start, go to next test.

Scheme 99

TEST 5, DETERMINE MISSING SPARK COMBINATION

If during cranking spark is missing from both cylinders No. 1 and 4 plug wires or both cylinders No. 2 and 3 plug wires, go to next test. If spark is present, go to TEST 7.

TEST 6, CHECK PLUGS & WIRES

Check spark plug wires for insulation damage, looseness, shorting or other damage. Remove and check spark plugs for damage, wear, carbon deposits and proper plug gap. If spark plug wires and spark plugs are good, reinstall, and go to next test. If components are faulty, service or replace as required. If vehicle still does not start, go to next test.

TEST 7, CHECK DIS MODULE VBAT

Install diagnostic cable. Connect diagnostic cable to breakout box. Use 2.3L overlay. Connect LED test light between breakout box pins No. (-) J2 (IGND D) and (+) J5 (VBAT D). Turn key on. If test light is on, go to next test. If test light is not on, check connectors, repair or replace harness and check for fault codes. If vehicle still does not start, go to next test.

TEST 8, CHECK DIS MODULE IGNITION GROUND

With key off, check resistance between breakout box pins No. J2 (IGND D) and J60 (BAT -). If resistance is more than 5 ohms, go to next test. If resistance is less than 5 ohms, go to TEST 10.

TEST 9, CHECK DIS MODULE MOUNTING SCREWS

Check DIS module mounting screws for corrosion or looseness. If mounting screws are clean and tight, replace DIS module, and check for fault codes. If screws are not clean and tight, clean or replace screws. Clean mounting area on DIS module. Check for fault codes. If vehicle still does not start, go to next test.

TEST 10, CHECK RIGHT COIL PACK CIRCUITS

With key on, connect LED test light between breakout box pins No. (+) J18 (RC1D) and (-) J60 (BAT -). Connect test light between breakout box pins No. (+) J10 (RC2D) and (-) J60 (BAT -). If test light does not illuminate in both tests, go to next test. If test light illuminates in both tests, go to TEST 14.

TEST 11, RIGHT COIL PACK FAULT, ISOLATE DIS MODULE

With key off, disconnect diagnostic cable connector from DIS module (Pins No. 7-12). (Scheme 100) Repeat test procedures in TEST 10. If test light illuminates during both tests, replace DIS module, and check for fault codes. See TESTS W/CODES article in the ENGINE PERFORMANCE Section. If test light does not illuminate during both tests, go to next test.

Scheme 100

TEST 12, CHECK RIGHT COIL PACK VBAT

Connect LED test light between breakout box pins No. (+) J26 (VBAT R) and (-) J60 (BAT -). If test light illuminates, go to next test. If test light does not illuminate, check connectors, repair or replace harness and check for fault codes. If vehicle still does not start, go to next test.

TEST 13, CHECK RIGHT COIL CIRCUIT

Connect LED test light between breakout box pins No. (+) J23 (RC1C) and (-) J60 (BAT -). Connect LED test light between breakout box pins No. (+) J24 (RC2C) and (-) J60 (BAT -).

If test light illuminates during both tests, one or both coil wires are shorted to VBAT. Repair connectors and harness, and check for fault codes. If test light does not illuminate during both tests, replace right coil pack, and check for fault codes. If vehicle still does not start, go to next test.

TEST 14, CHECK PIP D AT DIS MODULE

Connect LED test light between breakout box pins No. (+) J32 (PIP D) and (-) J60 (BAT -). Crank engine. If test light blinks continuously during crank, go to next test. If test light does not blink continuously during crank, go to TEST 19.

TEST 15, CHECK DIS MODULE COIL DRIVERS

Connect LED test light between breakout box pins No. (+) J18 (RC1D) and (-) J60 (BAT -). Crank engine. Connect test light between breakout box pins No. (+) J10 (RC2D) and (-) J60 (BAT -). Crank engine.

If test light blinks continuously during both tests, go to next test. If test light does not blink continuously during both tests, replace DIS module, and check for fault codes. If vehicle still does not start, go to next test.

TEST 16, CHECK RIGHT COIL PACK VBAT

Connect LED test light between breakout box pins No. (+) J26 (BAT R) and (-) J60 (BAT -). If test light illuminates, go to next test. If test light does not illuminate, check connectors, repair or replace harness and check for fault codes. If vehicle still does not start, go to next test.

TEST 17, CHECK RIGHT COIL CIRCUIT

Connect LED test light between breakout box pins No. (+) J23 (RC1C) and (-) J60 (BAT -). Connect test light between breakout box pins No. (+) J24 (RC2C) and (-) J60 (BAT -).

If test light illuminates in both tests, go to next test. If test light does not illuminate in both tests, one or both coil wires is shorted to ground or coil pack may be damaged. Check connectors, and repair or replace harness. Check for fault codes. If vehicle still does not start, go to next test.

TEST 18, CHECK RIGHT COIL CIRCUIT

Repeat test procedures in TEST 17, but crank engine during each test connection. If test light blinks continuously during each test, replace right coil pack, and check for fault codes. If test light does not blink continuously during each test connection, one or both coil wires are open. Check connectors, and service or replace harness. Check for fault codes. If vehicle still does not start, go to next test.

TEST 19, ISOLATE DIS MODULE FROM PIP D

With key off, disconnect diagnostic cable connector from DIS module (Pins No. 1-6). (Scheme 100) Connect LED test light between breakout box pins No. (+) J32 (PIP D) and (-) J55 (IGND S). Crank engine. If test light does not blink continuously, go to next test. If test light blinks continuously, go to TEST 26.

TEST 20, CHECK CRANKSHAFT SENSOR VBAT

With key on, connect LED test light between breakout box pins No. (+) J56 (VBAT S) and (-) J2 (IGND D). If test light illuminates, go to next test. If test light does not illuminate, check connectors. Repair or replace harness. Check for fault codes. If vehicle still does not start, go to next test.

TEST 21, CHECK CRANKSHAFT SENSOR IGNITION GROUND

With key off, disconnect ECA. Disconnect diagnostic cable connector from crankshaft sensor. Connect an ohmmeter between breakout box pins No. J55 (IGND S) and J60 (BAT -).

If resistance is less than 5 ohms, go to next test. If resistance is not less than 5 ohms, check connectors, repair or replace harness and check for fault codes. If vehicle still does not start, go to next test.

TEST 22, CHECK CRANKSHAFT SENSOR PIP S

Connect ECA. Connect diagnostic cable connector to crankshaft sensor. Connect LED test light between breakout box pins No. (+) J33 (PIP S) and (-) J2 (IGND D). Crank engine.

If test light blinks continuously, PIP is open between sensor and DIS module. Check connectors, and repair or replace harness. Check for fault codes. If vehicle still does not start, go to next test. If test light does not blink continuously, go to next test.

TEST 23, CHECK PIP CIRCUIT FOR SHORT TO GROUND

With key off, disconnect diagnostic cable connector from crankshaft sensor. Disconnect diagnostic cable connector from DIS module (Pins No. 1-6). (Scheme 100) Connect LED test light between breakout box pins No. (-) J33 (PIP S) and (+) J57 (BAT+). Turn key on.

If test light does not illuminate, go to next test. If test light illuminates, PIP is shorted to ground between sensor and DIS module. Check connectors, repair or replace harness and check for fault codes. If vehicle still does not start, go to next test.

TEST 24, CHECK PIP CIRCUIT FOR SHORT TO VBAT

Connect LED test light between breakout box pins No. (+) J33 (PIP S) and (-) J60 (BAT -). If test light does not illuminate, go to next test. If test light illuminates, PIP is shorted to VBAT between sensor and DIS connectors. Repair or replace harness. Check for fault codes. If vehicle still does not start, go to next test.

TEST 25, CHECK CRANKSHAFT VANE

Crank engine. If crankshaft vane moves through sensor air gap, replace crankshaft sensor, and check for fault codes. If crankshaft vane does not move through sensor air gap, inspect components contributing to operation of crankshaft vane and sensor. Repair as necessary.

TEST 26, ISOLATE EEC-IV PROCESSOR (ECA) FROM PIP CIRCUIT

With key off, reconnect diagnostic cable connector to DIS module (Pins No. 1-6). (Scheme 100) Disconnect ECA. Crank engine. If test light does not blink continuously, go to next test. If test light blinks continuously, replace ECA. Check for fault codes. If vehicle still does not start, go to next test.

TEST 27, CHECK PIP EEC CIRCUIT FOR SHORT TO VBAT

With key off, disconnect diagnostic cable connector from DIS module (Pins No. 1-6). (Scheme 100) Connect LED test light between breakout box pins No. (+) J31 (PIP EEC) and (-) J60 (BAT -). Turn key on. If test light does not illuminate, go to next test. If test light illuminates, PIP EEC is shorted to BAT. Check connectors, repair or replace harness and check for fault codes. If vehicle still does not start, go to next test.

TEST 28, CHECK PIP EEC CIRCUIT FOR SHORT TO GROUND

Connect LED test light between breakout box pins No. (-) J31 (PIP EEC) and (+) J57 (BAT+). If test light illuminates, PIP EEC is shorted to ground. Check connectors, repair or replace harness and check for fault codes. If test light does not illuminate, replace DIS module, and check for fault codes.

Scheme 101

Repair any fault codes as necessary. See TESTS W/CODES article in the ENGINE PERFORMANCE Section. If no fault codes are retrieved, proceed to next test.

Using Neon Bulb Spark Tester (D89P-6666-A) or Air Gap Spark Tester (D81P-6666-A), check for spark at all spark plug wires while cranking. If spark is present and consistent on all spark plug wires, go to next test. If spark is not present on all wires, go to TEST 7.

TEST 3, CHECK PIP AT EDIS MODULE

DO NOT connect ECA to break- out box while performing EDIS diagnostics unless so directed. Turn key off. Connect EDIS Diagnostic Cable (007-00059) to breakout box (T83L-50-EEC-IV), EDIS module and coil pack. DO NOT connect VR sensor tee. (Scheme 102) Use EDIS No. 6 overlay.

Connect EDIS diagnostic cable negative lead to battery, leaving positive lead disconnected. Set EDIS diagnostic cable box to 4/6 CYLINDER position. Set DVOM to 20-volt AC scale. Connect DVOM leads between breakout box pins No. J43 (PIP E) and J7 (BAT -). Crank engine. If settled AC voltage reading is greater than 0.4 volts, go to next test. If settled AC voltage reading is less than 0.4 volts, go to TEST 8.

Scheme 102

TEST 4, CHECK PIP CONTINUITY TO EEC

Turn key off. Ensure ECA is disconnected. Set DVOM to 2-k/ohm scale. Measure resistance between breakout box pin No. J43 (PIP E) and vehicle harness connector pin No. 56 (PIP). (Scheme 99)

If resistance is less than 5 ohms, go to next test. If resistance is greater than 5 ohms, repair open circuit. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and run QUICK TEST. See TESTS W/CODES article in the ENGINE PERFORMANCE Section.

TEST 5, CHECK IGND AT EDIS

With key off and ECA disconnected, check resistance between breakout box pins No. J47 (IGND E) and J7 (BAT -). If resistance is less than 1025 ohms, go to TEST 6. If resistance is greater than 1025 ohms, go to TEST 11.

TEST 6, CHECK IGND CONTINUITY TO EEC

With key off and ECA disconnected, check resistance between breakout box pin No. J47 (IGND E) and vehicle harness connector pin No. 16 (IGN GND). (Scheme 99) If resistance is less than 1025 ohms, remove all test equipment. Reconnect all components. Clear Continuous Memory, and run QUICK TEST. See TESTS W/CODES article in the ENGINE PERFORMANCE Section.

If Continuous Memory Code 16 or 18 is present, go to TEST 32. If no codes are present, go to TROUBLE SHOOTING-NO CODES article for other possible causes of no-start. If resistance is greater than 1025 ohms, repair open circuit, and remove all test equipment. Reconnect all components, and check for fault codes.

TEST 7, CHECK PLUGS & WIRES

Check spark plug wires for insulation damage, looseness, shorting or other damage. Remove spark plugs, and check plugs for damage, wear, carbon deposits and proper plug gap. If spark plugs and spark plug wires are good, reinstall, and go to TEST 12. If any components are not good, repair or replace as required. Remove all test equipment, and check for fault codes.

TEST 8, ISOLATE EDIS MODULE/PIP FAULT

With key off, connect EDIS diagnostic cable positive lead to battery positive. Set DVOM to 20-volt AC scale. Hold EDIS diagnostic cable PIP push button down. Crank engine, and measure voltage breakout box pins No. J43 (PIP E) and J7 (BAT -).

If settled AC voltage is greater than one volt, go to next test. If settled AC voltage is less than one volt, there is no PIP output from EDIS module. Replace EDIS module, and remove all test equipment. Reconnect all components, and check for fault codes.

TEST 9, CHECK PIP CIRCUIT FOR SHORT TO GROUND

With key off and ECA disconnected, disconnect EDIS module from EDIS module tee. Leave EDIS cable connected to EDIS module side of vehicle harness connector. Disconnect EDIS diagnostic cable positive lead from battery positive. Set DVOM to 2-k/ohm scale. Measure resistance between breakout box pins No. J43 (PIP E) and J7 (BAT -).

If resistance is less than 5 ohms, PIP is shorted to ground in harness. Check connectors, and repair or replace harness. Check for fault codes. If resistance is greater than 5 ohms, go to next test.

TEST 10, CHECK PIP CIRCUIT FOR SHORT TO POWER

With key off and ECA disconnected, set DVOM to 2-k/ohm scale. Measure resistance between breakout box pins No. J43 (PIP E) and J1 (BAT +). If resistance is less than 5 ohms, PIP is shorted in harness. Check connectors, and repair or replace harness. Check for fault codes. If resistance is greater than 5 ohms, replace ECA. Clear Continuous Memory, and check for fault codes.

TEST 11, CHECK PWR GND TO EDIS MODULE

With key off, set DVOM to 2-k/ohm scale. Measure resistance between breakout box pins No. J27 (PWR GND) and J7 (BAT -). If resistance is less than 5 ohms, replace EDIS module. Remove all test equipment, and check for fault codes. If resistance is greater than 5 ohms, repair open circuit, reconnect all components and check for fault codes. If vehicle still does not start, go to next test.

TEST 12, CHECK PERF. W/O EDIS DIAGNOSTIC CABLE INSTALLED

If original symptom was crank but no start, go to next test. If original symptom was not crank but no start, go to TEST 46.

TEST 13, CHECK PWR GND TO EDIS MODULE

Turn key off. Disconnect ECA. Install EDIS diagnostic cable, and connect it to breakout box, EDIS module and coil pack. Do not connect VR sensor tee. Connect diagnostic cable negative lead to battery negative terminal, leaving positive lead disconnected. Set diagnostic cable box switch to 4/6 CYLINDER position. Set DVOM to 2-k/ohm scale. Measure resistance between breakout box pins No. J27 (PWR GND) and J7 (BAT -).

If resistance is less than 5 ohms, go to next test. If resistance is greater than 5 ohms, repair open circuit. Remove all test equipment, and reconnect all components. Check for fault codes. If vehicle still does not start, go to next test.

TEST 14, CHECK FOR VBAT OPEN TO EDIS MODULE

With key off and ECA disconnected, set DVOM to 20-volt scale. Measure voltage between breakout box pins No. (+) J51 (VBAT E) and (-) J7 (BAT -). If voltage is greater than 10.5 volts, go to next test. If voltage is less than 10.5 volts, repair open circuit. Remove all test equipment, reconnect all components and check for fault codes.

TEST 15, CHECK VRS+ BIAS AT EDIS MODULE

With key off and ECA disconnected, set DVOM to 20-volt scale. Measure voltage between breakout box pins No. (+) J35 (VRS+ E) and (-) J7 (BAT -). If voltage is 0.8-2.2 volts, go to next test. If voltage is not 0.8-2.2 volts, go to TEST 17.

TEST 16, CHECK VRS AMPLITUDE AT EDIS MODULE

With key off and ECA connected to breakout box, disconnect diagnostic cable negative lead from battery negative terminal. Set DVOM to 20-volt AC scale. Crank engine, and measure voltage between breakout box pins No. J35 (VRS+ E) and J48 (VRS E). If settled voltage is greater than 0.4 volt, go to TEST 46. If settled voltage is less than 0.4 volt, go to TEST 25.

TEST 17, CHECK VRS+ BIAS/ISOLATE VRS/BIAS FAULT

With key off and ECA disconnected, disconnect VR sensor from vehicle harness connector. Set DVOM to 20-volt scale. Turn key on, but leave engine off. Measure voltage between breakout box pins No. (+) J35 (VRS+ E) and (-) J7 (BAT -). If voltage is not 0.8-2.2 volts, go to next test. If voltage is 0.8-2.2 volts, go to TEST 21.

TEST 18, CHECK VRS+ HIGH OR LOW/BIAS FAULT

If voltage in TEST 17 was less than 0.8 volt, go to next test. If voltage in TEST 17 was greater than 2.2 volts, go to TEST 20.

TEST 19, CHECK VRS+ CIRCUIT FOR SHORT TO GROUND

With key off and ECA disconnected, disconnect EDIS module from EDIS module tee, leaving diagnostic cable connected to vehicle harness connector. Set DVOM to 2-k/ohm scale. Measure resistance between breakout box pins No. J35 (VRS+ E) and J7 (BAT -).

If resistance is less than 1025 ohms, repair short circuit. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes. If resistance is greater than 1025 ohms, replace EDIS module. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.

TEST 20, CHECK VRS+ CIRCUIT FOR SHORT TO VBAT

With key off and ECA disconnected, disconnect EDIS module from EDIS module tee, leaving diagnostic cable connected to vehicle harness connector. Set DVOM to 20-volt scale. Turn key on, but leave engine off. Measure voltage between breakout box pins No. (+) J35 (VRS+ E) and (-) J7 (BAT -).

If voltage is greater than 0.5 volt, repair short in harness. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes. If voltage is less than 0.5 volt, replace EDIS module. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.

TEST 21, CHECK VRS BIAS

With key off and ECA disconnected, set DVOM to 20-volt scale. Turn key on, but leave engine off. Measure voltage between breakout box pins No. (+) J48 (VRS E) and (-) J7 (BAT -). If voltage is 0.8-2.2 volts, replace VR sensor. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes. If voltage is not 0.8-2.2 volts, go to next test.

TEST 22, CHECK VRS HIGH OR LOW/BIAS FAULT

If voltage in TEST 21 was less than 0.8 volt, go to next test. If voltage in TEST 21 was greater than 2.2 volts, go to TEST 24.

TEST 23, CHECK VRS CIRCUIT FOR SHORT TO GROUND

With key off and ECA disconnected, disconnect EDIS module from EDIS module tee, leaving diagnostic cable connected to vehicle harness connector. Set DVOM to 2-k/ohm scale. Measure resistance between breakout box pins No. J48 (VRS E) and J7 (BAT -).

If resistance is less than 1025 ohms, repair short circuit. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes. If resistance is greater than 1025 ohms, replace EDIS module. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.

TEST 24, CHECK VRS CIRCUIT FOR SHORT TO VBAT

With key off and ECA disconnected, disconnect EDIS module from EDIS module tee, leaving diagnostic cable connected to vehicle harness connector. Set DVOM to 20-volt scale. Turn key on, but leave engine off. Measure voltage between breakout box pins No. J48 (VRS E) and J7 (BAT -).

If voltage is greater than 0.5 volt, repair short circuit. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes. If voltage is less than 0.5 volt, replace EDIS module. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.

TEST 25, CHECK VRS AMPLITUDE AT EDIS MODULE

With key off and ECA disconnected, disconnect EDIS module from EDIS module tee, leaving diagnostic cable connected to vehicle harness connector. Set DVOM to 20-volt AC scale. Crank engine, and measure voltage between breakout box pins No. J35 (VRS+ E) and J48 (VRS E).

If settled voltage is greater than 0.4 volt, replace EDIS module. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes. If settled voltage is less than 0.4 volt, go to next test.

TEST 26, CHECK VRS RESISTANCE

With key off and ECA disconnected, connect EDIS diagnostic cable negative lead to negative battery terminal. Set DVOM to 20-k/ohm scale. Measure resistance between breakout box pins No. J48 (VRS E) and J35 (VRS+ E). If resistance is 2580-2700 ohms, go to next test. If resistance is not 2580-2700 ohms, go to TEST 28.

TEST 27, CHECK VRS AIR GAP & TRIGGER WHEEL

With key off, inspect trigger wheel for damage. Check VRS air gap. If air gap and trigger wheel are okay, replace VR sensor. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.

If air gap and trigger wheel are damaged, repair or replace damaged components. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.

TEST 28, CHECK VRS HIGH OR LOW RESISTANCE

With key off and ECA disconnected, disconnect EDIS diagnostic cable negative lead from battery. Set DVOM to 20-k/ohm scale. Measure resistance between breakout box pins No. J48 (VRS E) and J35 (VRS+ E). If resistance is less than 2550 ohms, go to next test. If resistance is greater than 2550 ohms, go to TEST 30.

TEST 29, CHECK VRS+ SHORTED TO VRS

With key off and ECA disconnected, disconnect VR sensor from vehicle harness connector. Set DVOM to 20-k/ohm scale. Measure resistance between breakout box pins No. J35 (VRS+ E) and J48 (VRS E).

If resistance is greater than 3 k/ohms, replace VR sensor. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes. If resistance is less than 3 k/ohms, repair short circuit. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.

TEST 30, CHECK VRS+ FOR OPEN CIRCUIT

With key off and ECA disconnected, connect VR sensor tee to VR sensor and vehicle harness connector. Set DVOM to 20-k/ohm scale. Measure resistance between breakout box pins No. J31 (VRS+ S) and J35 (VRS+ E).

If resistance is less than 2025 ohms, go to next test. If resistance is greater than 2025 ohms, repair open circuit. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.

TEST 31, CHECK VRS FOR OPEN CIRCUIT

With key off and ECA disconnected, set DVOM to 20-k/ohm scale. Measure resistance between breakout box pins No. J32 (VRS S) and J48 (VRS E).

If resistance is less than 2025 ohms, replace VR sensor. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes. If resistance is greater than 2025 ohms, repair open circuit. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.

Note. Tests 32-37 may also be used for diagnosing KOEO Code 16, Continuous Memory Code 18 and/or "CHECK ENGINE" light on: IDM failure.

TEST 32, CHECK FOR IDM SHORT HIGH

Turn key off. Connect EDIS Diagnostic Cable (007-00059) to breakout box (T83L-50-EEC-IV), EDIS module and coil pack. DO NOT connect VR sensor tee. (Scheme 102) Use EDIS No. 6 overlay. Connect EDIS diagnostic cable negative and positive leads to battery. Set EDIS diagnostic cable box switch to 4/6 CYLINDER position. Set DVOM to 20-volt scale.

Crank engine, and measure voltage between breakout box pins No. J30 (EDIS diagnostic cable IDM detector) and J7 (BAT -). If pulses are present, IDM detector output will be 5-7 volts DC. If pulses are present, go to next test. If pulses are not present, go to TEST 34.

TEST 33, CHECK FOR IDM OPEN CIRCUIT

With key off and ECA disconnected, disconnect EDIS module from EDIS module tee. Leave EDIS diagnostic cable connected to vehicle harness connector. Set DVOM to 200-ohm scale. Measure resistance between breakout box pin No. J41 (IDM E) and vehicle harness connector pin No. 4. (Scheme 99)and (Scheme 103).

If resistance is less than 5 ohms, replace ECA. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes. If resistance is greater than 5 ohms, repair open circuit. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.

Scheme 103

TEST 34, CHECK IDM OUTPUT FROM EDIS MODULE

With key off and ECA connected, set DVOM to 20-volt scale. Push EDIS IDM button at EDIS diagnostic cable connector to breakout box. Crank engine, and measure voltage between breakout box pins No. J30 (EDIS diagnostic cable IDM detector) and J7 (BAT -). If voltage is 5-7 volts, go to next test. If voltage is not 5-7 volts, replace EDIS module. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.

TEST 35, CHECK FOR IDM SHORT IN ECA

With key off and ECA disconnected, set DVOM to 20-volt scale. Crank engine, and measure voltage between breakout box pins No. J30 (EDIS diagnostic cable IDM detector) and J7 (BAT -). If voltage is 4.5-6.0 volts, replace ECA. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes. If voltage is not 4.5-6.0 volts, go to next test.

TEST 36, CHECK FOR IDM SHORT TO GROUND IN HARNESS

With key off and ECA disconnected, disconnect EDIS module from EDIS module tee. Leave EDIS cable connected to vehicle harness connector. Set DVOM to 20-k/ohm scale. Measure resistance between breakout box pins No. J41 (IDM E) and J7 (BAT -). If resistance is less than 5 ohms, repair short circuit. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes. If resistance is greater than 5 ohms, go to next test.

TEST 37, CHECK FOR IDM SHORT TO VBAT IN HARNESS

With key off and ECA disconnected, set DVOM to 20-volt scale. Turn key on, leaving engine off. Measure voltage between breakout box pins No. (+) J41 (IDM E) and (-) J7 (BAT -). If voltage is greater than 0.5 volt, IDM is shorted to VBAT between EDIS module and ECA. Repair short circuit. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.

If voltage is less than 0.5 volt, IDM is shorted to another wire between EDIS module and ECA. Repair short or replace harness. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.

Note. Tests 38-45 may also be used for diagnosing KOER Code 18.

TEST 38, CHECK BASE TIMING

Turn key off. Connect EDIS Diagnostic Cable (007-00059) to breakout box (T83L-50-EEC-IV), EDIS module and coil pack. DO NOT connect VR sensor tee. (Scheme 102) Use EDIS No. 6 overlay. Connect EDIS diagnostic cable negative and positive leads to battery. Set EDIS diagnostic cable box switch to 4/6 CYLINDER position. Connect timing light (must be DIS/EDIS compatible).

Start engine, and bring to normal operating temperature. Check timing. If timing is 10+/-2 degrees BTDC when EDIS diagnostic cable SAW DETECTOR button is pushed, go to next test. If timing is not 10+/-2 degrees BTDC when EDIS diagnostic cable SAW DETECTOR button is pushed, go to TEST 45.

TEST 39, CHECK ADVANCE SPARK ANGLE

If engine timing is greater than 15 degrees BTDC when EDIS diagnostic cable SAW DETECTOR button is released, EDIS ignition is functioning normally. Go to TROUBLE SHOOTING-NO CODES article for other possible causes of symptoms. If timing is less than 15 degrees BTDC when EDIS diagnostic cable SAW DETECTOR button is released, go to next test.

TEST 40, CHECK SAW AT EDIS MODULE

With key off, set DVOM to 20-volt scale. Start engine, and measure voltage between breakout box pins No. (+) J21 (EDIS diagnostic cable SAW detector) and (-) J7 (BAT -). If voltage is 5-7 volts, replace EDIS module. If voltage is not 5-7 volts, go to next test.

TEST 41, CHECK SAW FOR SHORT IN EDIS MODULE

With key off, connect ECA. Set DVOM to 20-volt scale. Push EDIS diagnostic cable SAW button. Start engine, and measure voltage between breakout box pins No. (+) J21 (EDIS diagnostic cable SAW detector) and (-) J7 (BAT -). If voltage is 5-7 volts, SAW is shorted in EDIS module. Replace EDIS module. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes. If voltage is not 5-7 volts, go to next test.

TEST 42, CHECK FOR SAW SHORT TO GROUND IN HARNESS

Turn key off, and disconnect ECA. Disconnect EDIS module from EDIS module tee, leaving EDIS diagnostic cable connected to vehicle harness connector. Disconnect Heated Exhaust Gas Oxygen Sensor (HEGO) connector. Set DVOM to 200-ohm scale. Measure resistance between breakout box pins No. J45 (SAW E) and J7 (BAT -). If resistance is less than 100 ohms, repair short circuit. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes. If resistance is greater than 100 ohms, reconnect HEGO, and go to next test.

TEST 43, CHECK FOR SAW SHORT TO VBAT IN HARNESS

With key off and ECA disconnected, set DVOM to 20-volt scale. Turn key on, but leave engine off. Measure voltage between breakout box pins No. (+) J45 (SAW E) and (-) J7 (BAT -). If voltage is less than 0.5 volt, repair short circuit. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes. If voltage is greater than 0.5 volt, go to next test.

TEST 44, CHECK FOR SAW OPEN

With key off and ECA disconnected, set DVOM to 2-k/ohm scale. Measure resistance between breakout box pin No. J45 (SAW E) and vehicle harness connector pin No. 36. (Scheme 99) If resistance is less than 5 ohms, SAW is not being transmitted by ECA. Replace ECA. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes. If resistance is greater than 5 ohms, repair open circuit. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.

TEST 45, INSPECT VR SENSOR & TRIGGER WHEEL

If VR sensor or trigger wheel is damaged, loose or misaligned, repair or replace components as necessary. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes. If VR sensor or trigger wheel is not damaged, loose or misaligned, there is no PIP signal output from EDIS module. Replace EDIS module. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.

Note. Tests 46-56 may also be used for diagnosing Continuous Memory Code 45 and/or "CHECK ENGINE" light on: coil failure.

TEST 46, CHECK VBAT OPEN TO COIL

Turn key off, and connect ECA. Connect EDIS Diagnostic Cable (007-00059) to breakout box (T83L-50-EEC-IV), EDIS module and coil pack. DO NOT connect VR sensor tee. (Scheme 102) Use EDIS No. 6 overlay. Connect EDIS diagnostic cable negative to negative battery terminal, leaving positive lead disconnected. Set EDIS diagnostic cable box switch to 4/6 CYLINDER position. Set DVOM to 20-volt scale.

Turn key on, but leave engine off. Measure voltage between breakout box pins No. (+) J5 (VBAT C) and (-) J7 (BAT -). If voltage is greater than 10.5 volts, go to next test. If voltage is less than 10.5 volts, repair open circuit. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.

TEST 47, VERIFY VEHICLE OPERATING MODE

If vehicle will not crank and start, go to next test. If vehicle will crank and start, go to TEST 49.

TEST 48, CHECK C1, C2 & C3 AT COIL PACK

Turn key off, and connect ECA. Set DVOM to 20-volt AC scale. Crank engine, and measure voltage between breakout box pins No. J7 (BAT -) and J3 (C1), J7 and J6 (C2) and J7 and J10 (C3). If any settled voltage is less than 0.2 volt, replace coil pack. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes. If all settled voltage readings are greater than 0.2 volt, go to TEST 50.

TEST 49, CHECK C1, C2 & C3 AT COIL PACK

Turn key off, and connect ECA. Set DVOM to 20-volt AC scale. Start engine, and measure voltage between breakout box pins No. J7 (BAT -) and J3 (C1), J7 and J6 (C2) and J7 and J10 (C3). If any settled voltage is less than one volt, replace coil pack. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes. If all settled voltage readings are greater than one volt, go to next test.

TEST 50, CHECK C1, C2 & C3 AT COIL PACK

Turn key off, and disconnect ECA. Set DVOM to 20-volt scale. Turn key on, but leave engine off. Measure voltage between breakout box pins No. J7 (BAT -) and J3 (C1), J7 and J6 (C2) and J7 and J10 (C3). If each voltage reading is greater than 10.5 volts, go to next test. If each voltage reading is less than 10.5 volts, go to TEST 55.

TEST 51, CHECK C1, C2 & C3 AT EDIS

Turn key off, and disconnect ECA. Set DVOM to 20-volt scale. Turn key on, but leave engine off. Measure voltage between breakout box pins No. (-) J7 (BAT -) and J3 (C1), J7 and J6 (C2) and J7 and J10 (C3). If each voltage reading is greater than 10.5 volts, go to next test. If each voltage reading is less than 10.5 volts, repair open circuit. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.

TEST 52, CHECK C1, C2 & C3 AT COIL PACK

Turn key off, and disconnect ECA. Disconnect coil pack from coil pack tee, leaving EDIS diagnostic cable connected to vehicle harness connector. Set DVOM to 20-volt scale. Turn key on, but leave engine off. Measure voltage between breakout box pins No. J7 (BAT -) and J3 (C1), J7 and J6 (C2) and J7 and J10 (C3). If each voltage reading is greater than 0.5 volt, go to next test. If each voltage reading is less than 0.5 volt, go to TEST 54.

TEST 53, CHECK C1, C2 & C3 AT COIL PACK

Turn key off, and disconnect ECA. Disconnect EDIS module from EDIS module tee, leaving EDIS diagnostic cable connected to vehicle harness connector. Set DVOM to 20-volt scale. Turn key on, but leave engine off. Measure voltage between breakout box pins No. J7 (BAT -) and J3 (C1), J7 and J6 (C2) and J7 and J10 (C3).

If each voltage reading is less than 0.5 volt, replace EDIS module. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes. If each voltage reading is greater than 0.5 volt, repair short circuit. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.

TEST 54, CHECK C1, C2 & C3 COIL PRIMARY

Turn key off, and disconnect ECA. Reconnect coil pack to coil tee. Set DVOM to 2-k/ohm scale. Measure resistance between breakout box pins No. J5 (VBAT C) and J3 (C1), J5 and J6 (C2) and J5 and J10 (C3). If each resistance is greater than 0.8 ohms, replace EDIS module. If any resistance is less than 0.8 ohms, replace coil pack. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.

TEST 55, CHECK C1, C2 & C3 FOR SHORT TO GROUND

Turn key off, and disconnect ECA. Set DVOM to 2-k/ohm scale. Measure resistance between breakout box pins No. J7 (BAT -) and J3 (C1), J7 and J6 (C2) and J7 and J10 (C3). If each resistance is less than 1200 ohms, go to next test. If each resistance is greater than 1200 ohms, replace coil pack. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.

TEST 56, CHECK C1, C2 & C3 FOR SHORT TO GROUND

Turn key off, and disconnect ECA. Disconnect EDIS coil tee from coil pack and vehicle harness connector. Disconnect EDIS module from EDIS module tee, leaving EDIS diagnostic cable connected to vehicle harness connector. Set DVOM to 2-k/ohm scale. Measure resistance between breakout box pins No. J7 (BAT -) and J3 (C1), J7 and J6 (C2) and J7 and J10 (C3).

If any resistance is less than 5 ohms, repair short circuit. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes. If resistance readings are greater than 5 ohms, replace EDIS module. Remove all test equipment, and reconnect all components. Clear Continuous Memory, and check for fault codes.

Scheme 104

1. Using a high output spark tester, check for spark at coil wire while cranking engine. If spark is present, go to step 2). If spark is not present, remove distributor cap, and crank engine to check for distributor rotation. If distributor rotation is okay, check coil secondary wire resistance. Resistance should not be greater than 7000 ohms per foot.
2. Place transmission in Neutral. Disconnect TFI wiring harness connector. Attach TFI Ignition Tester (105-000003). Connect Red lead of tester to 12 volts. Attach remote starter to "S" terminal of starter relay. While observing 2 LED lights on tester, use remote starter to crank engine. If PIP light blinks, go to step 4). If PIP light does not blink, remove distributor.
3. Remove TFI module from distributor. Using an ohmmeter, ensure all circuit resistance values are correct. See «TFI MODULE CIRCUIT RESISTANCE SPECIFICATIONS»(ref-22708-S33545363542001010300000). (Scheme 104) If readings are incorrect, replace TFI module. If readings are correct, check stator for open winding or short to ground. See I - SYS/COMP TESTS article in the ENGINE PERFORMANCE Section. TFI MODULE CIRCUIT RESISTANCE SPECIFICATIONS TFI Terminals (1) Ohms Ground Pin - PIP More than 500 Power Pin - PIP Input Pin Less than 2000 Power Pin - TFI Power Less than 200 Ground Pin - Ignition Ground Less than 2 PIP Input Pin - PIP Less than 200 (1) (Scheme 104)for terminal identification.
4. If TACH light did not blink in step 2), replace TFI module, and repeat step 1). If spark is still not present, replace ignition coil and module connector. If TACH light did blink in step 2), substitute ignition coil with a known working unit, and repeat step 1). If spark is now present, ensure coil secondary wire resistance is not greater than 7000 ohms per foot, and replace ignition coil.
5. If spark was not present in step 4), connect original vehicle coil and spark tester. Remove pin-in-line connector located near distributor. Crank engine while checking for spark. If spark is present, inspect PIP and ignition ground circuits to verify continuity, and repair as necessary.
6. If spark was not present in step 5), measure battery voltage with negative lead from voltmeter attached to base of distributor. Measure voltage at ignition coil positive (+) terminal. Ignition coil positive (+) terminal voltage should be at least 90 percent of battery voltage. If not, check circuitry between ignition coil and ignition switch for wear or damage. Repair as necessary.
7. If ignition coil positive (+) terminal voltage was at least 90 percent of battery voltage in step 6), remove connector from ignition module. Disconnect starter relay "S" terminal. Turn ignition on. Measure voltage at ignition module connector power terminals No. 3 and 4. (Scheme 104) See «TFI MODULE VOLTAGE TEST TERMINALS»(ref-22708-S02955097742001010300000). Voltage should be at least 90 percent of battery voltage.
8. If voltage is not at least 90 percent of battery voltage, check circuitry between ignition coil and ignition switch for wear or damage. Repair as necessary. If voltage was at least 90 percent of battery voltage in step 7), inspect wiring between ignition module terminal No. 2 and coil. If okay, check all related circuitry. Replace or repair as necessary.

TFI MODULE VOLTAGE TEST TERMINALS