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Home >> Ford >> 1996 >> Aerostar Van Window >> Repair and Diagnosis >> External Pages >> Different car >> Section 43 (Engine Controls - Tests W/Codes - 2.0L A/T) >> Tests >> Test NA - Distributor Ignition System Profile Ignition Pick-Up (Pip) CKT & Ignition Diagnostic Monitor (IDM) CKT >> Diagnostic Aids

Diagnostic Aids

WARNING: This page is about a different car, the 1995 Mazda MX-6 and 1995 Mazda 626. However, it is still accessible from the selected car via links, so may be relevant.

IDM is an input signal to the PCM that verifies spark plug fire based on ignition coil primary discharge. IDM signal consists of a single pulse for each engine RPM. No IDM pulse indicates secondary ignition misfire.

Perform this test when directed by QUICK TEST. This test is intended to diagnose EEC-IV portion of ignition system. For additional information on ignition system and component testing, see appropriate SYSTEM/COMPONENT TESTS - 2.0L article. To prevent replacing good components, be aware the following non-EEC related areas may be cause of problem:

1) Continuous Memory Code 211  Code 211 indicates 2 successive erratic Profile Ignition Pick-Up (PIP) pulses occurred, resulting in a possible engine miss or stall. Check for the following possible causes of fault:

If any of the listed possible causes are present, repair as necessary. Clear code and repeat QUICK TEST. If problem is not found, go to next step. If vehicle does not start, go to TEST AA.

2) Continuous Memory Code 212  Continuous Memory Code 212 indicates loss of IDM input to PCM. Possible causes for this fault are:

If vehicle is a no-start, see IGNITION SYSTEM in SYSTEM/COMPONENT TESTS - 2.0L . If vehicle starts, go to next step.

3) Check IDM Circuit Continuity  Turn ignition off. Disconnect PCM 60-pin connector and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Install Breakout Box (49-UN01-058), leaving PCM disconnected. Disconnect ICM. Measure resistance between test pin No. 4 at breakout box and IDM terminal at ICM wiring harness connector. If resistance is less than 5 ohms, go to step 5). If resistance is 5 ohms or more, repair open circuit and repeat QUICK TEST.

NOTE: A break in step numbering sequence occurs at this point. Procedure skips from step 3) to step 5). No test procedures have been omitted.

5) Check IDM Circuit For Short To Power (Except VREF)  Turn ignition off. Disconnect ICM. With breakout installed and PCM disconnected, measure voltage between test pin No. 4 at breakout box and negative battery terminal. Turn ignition on. Measure voltage between test pin No. 4 and test pins No. 40 and 60 at breakout box. If any reading is more than 10.5 volts, repair short circuit. Clear codes and repeat QUICK TEST. If both readings are 10.5 volts or less, go to next step.

6) Check IDM Circuit For Short To PIP & VREF  Turn ignition off. Disconnect ICM. Install breakout box with PCM disconnected. Check for shorts to PIP by measuring resistance between test pins No. 4 and No. 56 at breakout box. Check for shorts to VREF by measuring resistance between test pins No. 4 and No. 26 at breakout box. If each resistance is 10,000 ohms or less, repair short circuit. Remove breakout box, reconnect all components and repeat QUICK TEST. If each resistance is more than 10,000 ohms, go to next step.

7) Check IDM Circuit For Short To Ground  During this test, a short to SIG RTN (pin No. 46) may be indicated along with an actual short to PWR GND when 4-wire HO2S is connected to vehicle wiring harness. Turn ignition off. Disconnect ICM. With breakout box installed and PCM disconnected, measure resistance between test pin No. 4 and test pins No. 20, 40, 46 and 60 at breakout box. If each resistance is more than 10,000 ohms, go to next step. If any resistance is 10,000 ohms or less, repair short to ground in IDM circuit. Remove breakout box, reconnect all components and repeat QUICK TEST.

8) Check ICM  Turn ignition off. With breakout box installed, connect PCM to breakout box. Reconnect ICM. Connect DVOM between test pins No. 4 and 16 at breakout box. Start engine. Observe DVOM for voltage surge while lightly tapping on ICM to simulate road shock. Wiggle ICM wiring harness connector. If fault (voltage surge) is not indicated, go to next step. If fault (voltage surge) is indicated, disconnect and inspect wiring harness connectors and terminals for damage. Repair as necessary. If connectors and terminals are okay, check and repair ignition system as necessary. See IGNITION SYSTEM in SYSTEM/COMPONENT TESTS - 2.0L article.

9) Check EEC-IV Harness  Ensure engine is still running and DVOM is still connected between test pins No. 4 and 16 at breakout box. While observing DVOM, wiggle and bend wiring harness, a small section at a time, working way toward dash. Also, check harness from dash to PCM. If fault is indicated, isolate fault and repair as necessary. Remove breakout box, reconnect all components and repeat QUICK TEST. If no fault is found, go to next step.

10) Check PCM & Harness Connectors  Turn ignition off. Disconnect PCM 60-pin connector and inspect for damaged pins, corrosion and loose wires. Repair as necessary. Remove breakout box, reconnect all components and repeat QUICK TEST. If PCM connector is okay, go to next step.

11) Check PCM For Short To Power  Turn ignition off. With breakout box installed, connect PCM to breakout box. Disconnect CMP sensor. Measure voltage between test pin No. 4 at breakout box and chassis ground. Turn ignition on. Measure voltage between test pin No. 4 and test pins No. 40 and 60 at breakout box. If any reading is more than 10.5 volts, replace PCM. Remove breakout box, reconnect all components and repeat QUICK TEST. If both readings are 10.5 volts or less, go to next step.

12) Check PCM For Short To Ground  Turn ignition off. With breakout box installed, connect PCM to breakout box. Disconnect ICM and CMP sensor. Measure resistance between test pin No. 4 and test pins No. 40, 46 and 60 at breakout box. If all resistance readings are more than 10,000 ohms, check and repair ignition system as necessary. See IGNITION SYSTEM in SYSTEM/COMPONENT TESTS - 2.0L article. If any resistance reading is 10,000 ohms or less, replace PCM. Remove breakout box, reconnect all components and repeat QUICK TEST.

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