Diagnostic Aids

Enter this CIRCUIT TEST only when directed by CIRCUIT TEST C, CIRCUIT TEST J, CIRCUIT TEST PA, CIRCUIT TEST PB or CIRCUIT TEST PC.

This test is only intended to diagnose:

Power Control Module (PCM).
EEC power relay.
Ignition switch.
Wiring harness circuits (SIG RTN, PWR GND, VPWR, KAPWR and VREF).

To prevent replacement of good components, be aware the following non-EEC related areas and components may be cause of problem:

Battery cables and ground straps.
Voltage regulator.
Alternator.
Ignition switch.

Fig 1: Power Relay Circuits

TEST PIN NO. 1 (KAPWR) WIRE COLOR I.D.

Application	Wire Color
2.0L M/T	Blue/Red

TEST PIN NO. 17 (STO) WIRE COLOR I.D.

Application	Wire Color
2.0L M/T	Light Green/Red

TEST PIN NO. 37/57 (VPWR) WIRE COLOR I.D.

Application	Wire Color
2.0L	White/Red

TEST PIN NO. 46 (SIG RTN) WIRE COLOR I.D.

Application	Wire Color
2.0L M/T	Black/Blue

TEST PIN NO. 48 (STI) WIRE COLOR I.D.

Application	Wire Color
2.0L M/T	Blue/White

CAUTION: When battery is disconnected, PCM may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in the GENERAL INFORMATION section before disconnecting battery.

1) Battery Voltage Check Turn ignition on (engine off). Measure battery voltage. If voltage is less than 10.5 volts, recharge or replace battery. If voltage is 10.5 volts or more, go to step 2).

2) Check Continuity Of PWR GND Circuit Turn ignition off. Wait 10 seconds. Disconnect PCM, and inspect connector pins. If PCM connector pins are damaged, loose or corroded, repair as necessary. Install Breakout Box (T83L-50-EEC-IV), leaving PCM connected. Measure resistance between test pins No. 40 and 60 at breakout box and negative battery terminal. If resistance is 5 ohms or more, repair open in PWR GND circuit, and repeat QUICK TEST. If both resistances are less than 5 ohms, go to step 3).

3) Check For Open Between SIG RTN & PWR GND Circuits At PCM Ensure ignition is turned off. With breakout box installed and PCM connected, set DVOM on 200-ohm scale. Measure resistance between test pin No. 46 and test pins No. 40 and 60 at breakout box. If readings are 5 ohms or more, replace PCM and repeat QUICK TEST. If readings are less than 5 ohms, go to step 4).

4) Check Continuity Of SIG RTN Circuit Ensure ignition is turned off. Measure resistance between test pin No. 46 at breakout box and SIG RTN terminal of Data Link Connector (DLC). If resistance is 5 ohms or more, repair open in SIG RTN circuit and repeat QUICK TEST. If reading is less than 5 ohms, go to step 5).

5) Check KAPWR Circuit Voltage At EEC Power Relay Turn ignition off. Locate relay block in engine compartment. Disconnect EEC power relay from relay block. Turn ignition on. Measure voltage between negative battery terminal and KAPWR terminal at EEC power relay connector. If voltage is 10.5 volts or less, check KAPWR circuit between EEC power relay and positive battery terminal for open circuit. If voltage is 10.5 volts or more, go to step 6).

NOTE: Vehicles equipped with Power Distribution Boxes use a diode to provide electrical surge protection for the ignition switch and Ignition Control Module (ICM). If a no-start/no-code condition exists, ensure diode continuity in one direction only is present before going to step 6).

6) Check Ignition Circuit Voltage At EEC Power Relay Ensure PCM is connected to breakout box and EEC power relay is disconnected. Turn ignition on. Measure voltage between negative battery terminal and IGNITION terminal at EEC power relay connector. If voltage is less than 10.5 volts, repair open in ignition switch circuit and repeat QUICK TEST. If voltage is 10.5 volts or more, go to step 7).

7) Check PWR GND Circuit Continuity Turn ignition off, and wait 10 seconds. With PCM connected to breakout box, measure resistance between negative battery terminal and PWR GND terminal at EEC power relay connector. If resistance is 10 ohms or more, repair open circuit and repeat QUICK TEST. If reading is less than 10 ohms, go to step 8).

8) Check VPWR Circuit Continuity Turn ignition off. Measure resistance between test pins No. 37 and 57 (VPWR) at breakout box and VPWR terminal of EEC power relay connector. If resistance is 5 ohms or more, repair VPWR open circuit between EEC power relay and PCM. Repeat QUICK TEST. If reading is less than 5 ohms, go to step 9).

9) Check VPWR Circuit Voltage Turn ignition off. Install EEC power relay. Turn ignition on. With PCM connected, measure voltage between test pins No. 37 and 57 (VPWR) and test pins No. 40 and 60 (PWR GND) and 46 (SIG RTN) at breakout box. If voltage is 10.5 volts or more, repair circuit between PCM and EEC power relay. Repeat QUICK TEST. If voltage is less than 10.5 volts, replace EEC power relay. Repeat QUICK TEST.