Test Pin Identification
| Application | Wire Color | |
|---|---|---|
| Pin 12 (INJ 6) | Light Green/Orange | |
| Pin 15 (INJ 5) | Tan/Black | |
| Pin 35 (INJ 4) | Brown/Light Blue | |
| Pin 37 (VPWR) | Red | |
| Pin 39 (INJ 3) | Brown/Yellow | |
| Pin 40 (PWR GND) | Black/Light Green | |
| Pin 43 (HEGO-F) | Red/Black | |
| Pin 44 (HEGO-R) | ||
| Continental | Gray/Light Blue | |
| Sable & Taurus | Dark Blue/Light Green | |
| Pin 46 (SIG RTN) | Gray/Red | |
| Pin 49 (TOT) | Orange/Black | |
| Pin 57 (VPWR) | Red | |
| Pin 58 (INJ 1) | Tan | |
| Pin 59 (INJ 2) | White | |
| Pin 60 (PWR GND) | Black/Light Green | |
| Application | Wire Color |
|---|---|
| Pin 12 (INJ 6) | Light Green |
| Pin 15 (INJ 5) | Tan/Light Blue |
| Pin 35 (INJ 4) | Brown/Light Blue |
| Pin 39 (INJ 3) | Brown/Yellow |
| Pin 37 (VPWR) | Red |
| Pin 40 (PWR GND) | Black/Light Green |
| Pin 43 (HEGO-L) | Tan/Red |
| Pin 44 (HEGO-R) | Tan/Orange |
| Pin 46 (SIG RTN) | Black/White |
| Pin 57 (VPWR) | Red |
| Pin 58 (INJ 1) | Tan |
| Pin 59 (INJ 2) | White |
| Pin 60 (PWR GND) | Black/Light Green |
| Application | Wire Color |
|---|---|
| Pin 12 (INJ 6) | Light Green |
| Pin 15 (INJ 5) | Tan/Light Blue |
| Pin 29 (OCT ADJ) | Black/White |
| Pin 35 (INJ 4) | Brown/Light Blue |
| Pin 37 (VPWR) | Red |
| Pin 39 (INJ 3) | Brown/Yellow |
| Pin 40 (PWR GND) | Black/Light Green |
| Pin 43 (HEGO-L) | Tan/Red |
| Pin 44 (HEGO-R) | Tan/Orange |
| Pin 46 (SIG RTN) | Black/White |
| Pin 57 (VPWR) | Red |
| Pin 58 (INJ 1) | Tan |
| Pin 59 (INJ 2) | White |
| Pin 60 (PWR GND) | Black/Light Green |
1) Check For Contaminated Engine Oil Turn ignition off. Remove PCV valve from valve cover. Inspect valve cover hole and PCV for damage, sludge build up, blockage and movement of valve plunger. Repair as necessary. Perform KOER SELF-TEST. If vehicle is a no start, KOER codes 41/172, 91/136, 42/173 or 92/137, or Continuous Memory Codes 176, 177, 144/41, 91/139, 171, 175, 174 or 178 are set, reinstall PCV valve and go to next step. If no code is set, change engine oil and filter; reinstall PCV valve. Drive vehicle for 5 miles at 55 MPH. Rerun QUICK TEST.
2) Check Fuel Pressure Turn ignition off and wait 10 seconds. Install fuel pressure gauge. Ensure manifold vacuum supply is connected to fuel pressure regulator (if equipped). Run engine at idle and check fuel pressure. If vehicle will not start, cycle ignition on and off several times. For fuel pressure specifications, see FUEL PRESSURE SPECIFICATIONS article. If vehicle is a no start, cycle ignition on and off several times. If fuel pressure is within specification, go to next step. If pressure is not to specification, remove fuel pressure gauge. Repair electric fuel pump or fuel pressure regulator.
3) Check Systems Ability To Hold Fuel Pressure Turn ignition on, leaving engine off. If fuel pressure remains at specification for 60 seconds, go to next step (for no starts), go to step 5) (for PFI), or go to step 6) (for SPFI). If fuel pressure is not as described, repair fuel delivery system as necessary.
4) Fuel Delivery Test Ensure fuel is of good quality. With ignition off, install fuel pressure gauge and pressurize fuel system as in step 1). Disconnect inertia switch. Crank engine for 5 seconds. If fuel pressure drop is greater than 5 psi after 5 seconds of cranking, EEC-IV system is not the cause of no-start condition. Check additional no-start tests in the H - TESTS W/O NO CODES article in this section. If fuel pressure drop is less than 5 psi, remove fuel pressure gauge and reconnect inertia switch; go to step 7) (for PFI), or step 8) (for SPFI).
5) Cylinder Balance Test: PFI Engines Connect a tachometer to engine. Start engine and run at idle. Disconnect and reconnect injectors one at a time, noting RPM drop as each injector is disconnected. Note that ISC motor will attempt to re-establish RPM. If each injector does not produce a momentary drop in RPM, go to step 7). If each injector produces a momentary drop in RPM, go to step 13) (for symptoms or codes 41/172, 91/136 or 176), step 24) (for codes 42/173, 92/137 or 177), or step 14) (for all others).
6) Cylinder Balance Test: SPFI Engines ONLY Perform KOER SELF-TEST. After last code is displayed, wait 5-10 seconds. Enter CYLINDER BALANCE TEST by briefly opening throttle for one second (not WOT). Test time is approximately 2-3 minutes. A Code 77/538 indicates throttle is touched when the test is ran, and that test is not completed. To interpret codes received from test, refer to CYLINDER BALANCE TEST SERVICE CODES . If a Cylinder Balance Test Code is displayed, go to step 8). If a Cylinder Balance Test Code is not displayed, fuel delivery is okay; fault is in an area common to all cylinders. For symptoms or code 41/172, 91/136 or 176, go to step 13). For code 42/173, 92/137 or 177, go to step 24). For all other codes, go to step 14.
Code 538 could also be outputted if Continuous Memory Code 214 (CID) is present. If Continuous Memory Code 214 is present, see appropriate chart under SERVICE CODE REFERENCE CHARTS for instruction.
| Service Code | Application |
|---|---|
| 90 | Pass |
| 10 | Cylinder No. 1 |
| 20 | Cylinder No. 2 |
| 30 | Cylinder No. 3 |
| 40 | Cylinder No. 4 |
| 50 | Cylinder No. 5 |
| 60 | Cylinder No. 6 |
| 70 | Cylinder No. 7 |
| 80 | Cylinder No. 8 |
| 77/538 | Retest |
7) Check Injector & Harness Resistance: PFI Engines Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect pins for damage. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance of injector banks between test pins No. 37 and 58 (injector bank No. 1) or 59 (injector bank No. 2) at breakout box. Record resistance. Refer to appropriate INJECTOR BANK RESISTANCE table in this circuit test. If each resistance is within specifications for appropriate engine, go to step 12). If resistance is not as specified, repair open circuit on VPWR circuit (for no start), or go to step 9 (for all other conditions).
8) Check Injector & Harness Resistance: SPFI Engines Turn ignition off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect pins for damage. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure and record resistance between suspected injector circuit test pin and test pin No. 37. For no starts, measure and record resistance between any injector circuit test pin and test pin No. 37. Refer to appropriate INJECTOR BANK RESISTANCE table in this circuit test. If each resistance is within specifications for appropriate engine, go to step 12). If resistance is not as specified, repair open circuit on VPWR circuit (for no start), or go to step 9 (for all other conditions).
9) Check Continuity Of Fuel Injector Harness Turn ignition off and wait 10 seconds. Install breakout box, leaving ECA disconnected. Disconnect injector vehicle harness connector at injectors. Set DVOM to 200-ohm scale. Measure resistance between test pin No. 37/57 at breakout box and VPWR pin at each injector vehicle harness connector. See appropriate TEST SCHEMATIC in this circuit test. Measure resistance between injector test pin(s) at breakout box and the same injector circuit signal pin at each injector vehicle harness connector. If each resistance is less than 5 ohms, go to next step. If each resistance is greater than 5 ohms, repair open circuit. Remove breakout box, reconnect all components and drive vehicle for 5 miles at 55 MPH. Rerun QUICK TEST.
10) Check Injector Harness Circuit For Short To Power Or Ground Turn ignition off and wait for 10 seconds. With breakout box installed and ECA disconnected, disconnect fuel injector vehicle harness. See appropriate TEST SCHEMATIC in this circuit test. Set DVOM to 200-k/ohm scale. Measure resistance between injector test pin(s) and test pins No. 37/57, 40, 46 and 60. Measure resistance between injector test pin(s) at breakout box and chassis ground. If each resistance is greater than 10 k/ohms, replace injector per cylinder balance test service code and rerun QUICK TEST (for SPFI), or go to next step (for PFI). If each resistance is less than 10 k/ohms, repair short. Remove breakout box, reconnect all components and drive vehicle for 5 miles at 55 MPH. Rerun QUICK TEST.
11) Isolate Faulty Injector Circuit Turn ignition off. Install breakout box and disconnect ECA. Disconnect all injectors on suspected bank. With DVOM set on 200-ohm scale, connect one injector and measure resistance between test pins No. 37 and 58 or 59. Disconnect injector and repeat process for all other injectors. See appropriate INDIVIDUAL INJECTOR RESISTANCE table for specifications. If all injectors are within specifications, go to step 12). If injectors are not as specified, remove breakout box. Reconnect ECA and injectors. Repair open or short in injector harness. If circuit is okay, replace injector. Drive vehicle for 5 miles at 55 MPH. Rerun QUICK TEST.
12) Check Injector Drive Signal With ignition off and breakout box installed, connect ECA to breakout box. Use a non-powered 12-volt test light and connect as follows:
- PFI Engines - Connect test light between test pins No. 37 and 58 at breakout box. Connect light between test pins No. 37 and 59 at breakout box.
- Sequential PFI Engines (SPFI) - Connect test light between test pin No. 37 and the suspected injector(s) test pin at breakout box.
Crank or start engine. If test light glows dimly, system is operating properly. remove breakout box and reconnect ECA. Clean and test injectors. Drive vehicle for 5 miles at 55 MPH. Rerun QUICK TEST and CYLINDER BALANCE TEST.
If test light does not glow dimly (no light/bright light), check injector circuit for shorts to ground. If system is okay, remove breakout box and replace ECA. Remove breakout box and reconnect all components. Drive vehicle for 5 miles at 55 MPH. Rerun QUICK TEST.
13) Check Thermactor Operation If vehicle is equipped with Pulse-Air or does not have Thermactor System, ignore this step and go to next step. With dual HEGO, code 41/172 refers to right or rear HEGO, and code 91/136 or 176 refers to left or front HEGO. A HEGO that is always lean could be caused by Thermactor air being diverted upstream from HEGO sensor. Turn ignition off and wait 10 second. Disconnect Thermactor air hose(s) from Thermactor pump. Run KOER SELF-TEST. If codes 41/172, 91/136 or 176 are present, reconnect Thermactor air hose(s) and go to next step. If codes 41/172, 91/136 or 176 are not present, repair thermactor system as necessary.
14) Check HEGO Integrity A HEGO sensor that is always lean, slow to switch or does not switch could be caused by the following:
- Moisture inside HEGO sensor, or harness connector causing a short to ground
- HEGO sensor coated with containments
- HEGO circuit open
- HEGO circuit shorted to ground
Turn ignition off and wait 10 seconds. Inspect HEGO harness for chaffing, burns or other indications of damage; repair or replace as necessary. Inspect HEGO sensor and connector for signs of water entry; repair or replace as necessary. Start engine and run at 2000 RPM for 2 minutes. Turn ignition off and wait 10 seconds. Run KOER SELF-TEST. If fault codes are present, go to next step (for MAP sensor-equipped vehicles), or step 16) (for MAF sensor-equipped vehicles). If no code is present, go to step 21).
15) Checking HEGO Sensor On Engines With MAP Sensors Turn ignition off and set DVOM on 20-volt scale. Disconnect appropriate HEGO sensor from vehicle harness. Connect DVOM to HEGO SIGNAL lead at sensor connector and battery negative terminal (3-wire HEGO). Connect DVOM to HEGO SIGNAL and HEGO GND leads at sensor connector (4-wire HEGO). Disconnect and plug vacuum line MAP sensor. Start engine and apply 10-14 in Hg to Manifold Absolute Pressure (MAP) sensor. Run engine at 2000 RPM for 2 minutes. If reading is greater than 0.5 volt within 2 minutes, go to step 17). If reading is less than 0.5 volt within 2 minutes, replace HEGO sensor; reconnect MAP and rerun QUICK TEST.