Población y Muestra

To prevent replacement of good components, be aware that the following non-EEC related areas may be at fault: engine condition (valves, vacuum leaks, valve timing, EGR valve, etc.), PIP sensor, and TFI ignition module.

1) Perform KOER SELF-TEST and verify that SELF-TEST is activated. Check and record timing while in KOER SELF-TEST. System locks timing and then returns to normal 2 minutes after last service

code is displayed. If timing is 27-33

, spark timing is correct. Go to

KOER SELF-TEST. If timing is not 27-33

, go to next step. 2) Locate Spark Output (SPOUT) connector and open the

connection. Start engine and check for 10

BTDC base timing F 3

. If base timing is correct, reconnect SPOUT connector and go to next step. If base timing is not correct, adjust base timing. After timing is adjusted, reconnect SPOUT and perform TIMING CHECK. See TIMING CHECK in QUICK TEST (ALL VEHICLES) section of this article.

3) Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box. Turn key on, leaving engine off. With DVOM on 20-volt scale, measure voltage between test pins No. 37 and 40, and between test pins No. 57 and 60. If either reading is less than 10.5 volts, go to CIRCUIT TEST B, step 1). If both readings are 10.5 volts or more, go to next step.

4) Turn key off and wait 10 seconds. Disconnect harness connector at TFI module. With DVOM on 200-ohm scale, measure resistance between test pin No. 36 at breakout box and pin No. 2

(SPOUT circuit) at TFI harness connector. If reading is greater than 5 ohms, repair open circuit. Connect SPOUT connector and check timing as described in step 1). If reading is 5 ohms or less, go to next step. 5) Leave breakout box installed and TFI harness disconnected. Turn key off and set DVOM on 200-ohm scale. Measure resistance between test pin No. 16 at breakout box and pin No. 6 (IGN GRND circuit) at TFI harness connector. If reading is less than 5 ohms, go to CIRCUIT TEST A, step 7). If reading is 5 ohms or more, repair harness as necessary and repeat QUICK TEST.

Fig. 36: Spark Timing Check Circuit

TEST PP - NO CODES/CODES NOT LISTED

1) No Codes, Codes Not Listed. Turn key off and wait 10 seconds. Set DVOM on 20-volt scale. Disconnect Throttle Position

Sensor (TPS). Turn key on, leaving engine off. Measure voltage between VREF circuit at TPS harness connector and SIG RTN circuit in SELF-TEST connector. If reading is less than 4 volts or more than 6 volts, go to CIRCUIT TEST C, step 1). If reading is between 4 and 6 volts, connect TPS and go to next step.

2) Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box, leaving ECA

disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 48 and Self-Test Input (STI) at SELF-TEST connector pigtail. If reading is 5 ohms or more, repair open in circuit. If reading is less than 5 ohms, go to next step.

3) With breakout box installed and DVOM on 200-ohm scale, measure resistance between test pin No. 17 and Self-Test Output (STO) at SELF-TEST connector. If reading is 5 ohms or more, repair open in circuit. If reading is less than 5 ohms, go to next step.

4) Turn key off. With breakout box installed and DVOM on 200- ohm scale, measure resistance between test pin No. 49 and EGO sensor engine block ground. If reading is 5 ohms or more, repair EGO sensor ground wire or open circuit bad connection. If reading is less than 5 ohms, go to next step.

5) With breakout box installed and DVOM on 200-ohm scale, measure resistance between STO at SELF-TEST connector and engine block ground. If reading is 5 ohms or less, repair STO circuit for short to ground and repeat QUICK TEST. If reading is greater than 5 ohms, go to next step.

6) Turn key off. Install breakout box, and connect ECA to breakout box. Set DVOM on 20-volt scale. Connect DVOM between test pin No. 30 and test pins No. 40 or 60. Perform KEY ON/ENGINE RUNNING

(KOER) SELF-TEST. If reading is greater than one volt, repair

intermittent fault in NDS harness connector or switch. If okay, go to KOER SELF-TEST for appropriate service codes. If reading is not

greater than one volt, go to next step.

7) Leave key off and breakout box installed. Set DVOM on 20- volt scale. Connect DVOM between test pins No. 37 or 57 and between test pins No. 40 or 60. Turn key on and then off. Wait 10 seconds. If reading does not change from 10.5 volts (or higher) to zero volts, replace EEC power relay. Repeat QUICK TEST. If reading changes from 10.5 volts (or higher) to zero volts, go to next step only if vehicle is equipped with Malfunction Indicator Light (MIL) or Shift Indicator Light (SIL). If vehicle is NOT equipped with either of these lights, replace ECA. Repeat QUICK TEST.

NOTE: Malfunction Indicator Light (MIL) is displayed as "CHECK ENGINE" light on instrument cluster.

8) Malfunction Indicator Light (MIL) or Shift Indicator Light (SIL). If shift indicator light is always on or off, go to CIRCUIT TEST FF, step 1). If malfunction indicator light is always on, go to CIRCUIT TEST MM, step 1). If malfunction indicator light is always off, go to CIRCUIT TEST MM, step 2). If MIL or SIL is working normally, replace ECA and repeat QUICK TEST.

9) Continuous Code 15 Displayed. Clear continuous memory codes using procedure outlined in CONTINUOUS SELF-TEST. Repeat KOEO SELF-TEST through continuous memory code output. If continuous code 15 is not displayed, continuous code 15 testing is complete. If

continuous code 15 is displayed, go to next step.

NOTE: Continuous code 15 may be displayed when power to Keep Alive Memory (KAM) test pin No. 1 at ECA is interrupted. Code 15 may also be displayed the first time SELF-TEST is performed

and power is restored to ECA. Repeat SELF-TEST to ensure correct diagnosis.

10) Ensure that EEC components and wiring are not close to high tension secondary voltage wires or ignition components. If EEC wiring is close to high tension wires, reroute EEC wiring. Repeat QUICK TEST. If continuous code 15 is no longer displayed, continuous code 15 testing is complete. If continuous code 15 is still displayed, go to next step.

11) Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector and inspect for damage. Install breakout box, leaving ECA disconnected. Set DVOM on 20-volt scale. Connect DVOM positive test lead to test pin No. 1 and negative test lead to pins No. 40 or 60. Turn key on and observe voltage reading. If reading is less than 10.5 volts, repair open to KAM circuit. Repeat QUICK TEST. If reading is 10.5 volts or more, replace ECA and repeat QUICK TEST.

12) Output State Check Not Functioning. Turn key off and wait 10 seconds. Perform KOEO SELF-TEST and leave key on to enter OUTPUT STATE CHECK. If codes 23, 53, 63 or 68 are displayed, go to KOEO SELF- TEST table and service code(s) as instructed. If no codes are

displayed, go back to step 1). If code 11 (Pass) is displayed, go to next step.

13) Check throttle and linkage for sticking or binding. If throttle and linkage are okay, replace TPS and repeat QUICK TEST. If throttle and linkage are binding, repair as necessary and repeat QUICK TEST.

14) Power to ECA Check. Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if necessary. Install breakout box and set DVOM on 20-volt scale. Turn key on, leaving engine off.

Measure voltage between test pins No. 37 and 40, and between test pins No. 57 and 60. If either reading is less than 10.5 volts, go to

CIRCUIT TEST B, step 1). If both readings are 10.5 volts or more, replace ECA and repeat QUICK TEST.

15) Turn key off. Ensure that EEC wiring and components are more than 2" (50 mm) away from secondary ignition wires. Make sure that EEC wiring and components are more than 4" (100 mm) away from distributor, ignition coil, and starter motor and its wiring. If these items are correct, go to next step. If not, correct as necessary and repeat QUICK TEST.

16) Turn key off. Disconnect ECA 60-pin connector. Inspect connector for damaged pins, corrosion, or loose wires. Repair if

necessary. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between test pin No. 20 and chassis ground. If reading is less than 5 ohms, go to next step. If not, repair wiring harness and repeat QUICK TEST.

17) Turn key off. Connect ECA to breakout box, but disconnect harness from breakout box. Set DVOM on 200-ohm scale. Measure

resistance between test pin No. 20 and ECA metal case. If reading is less than 5 ohms, go to CIRCUIT TEST B, step 9). If reading is more than 5 ohms, replace ECA and repeat QUICK TEST.

Fig. 37: No Codes/Codes Not Listed Circuits

TEST QQ - SYSTEM CHECK

Perform this test ONLY after code 11 is displayed in KEY ON/ENGINE OFF (KOEO) SELF-TEST and you have been directed here from CIRCUIT TEST A, step 14) or by DIAGNOSIS BY SYMPTOM TEST.

1) ISC Check. If you are here for any reason other than engine stall or no start, go to next step. If engine stalls or if it does not start, attempt to start engine at part throttle. If engine runs roughly, go to next step. If engine runs smoothly at part

throttle, go to CIRCUIT TEST DD, step 4). If engine does not run, go to step 2).

2) MAP Check. Turn key off and disconnect MAP sensor. Connect MAP tester between harness and MAP sensor. Connect banana plugs of tester into DVOM and set DVOM on 20-volt scale. Turn key on and

measure sensor output voltage while cranking engine. If DVOM reading does not decrease from specified range, go to CIRCUIT TEST H, step 14). If DVOM reading decreases from specified range, go to next step. MAP VOLTAGE OUTPUT TABLE

Elevation (Ft.) Voltage Output (Volts) 0 ... 1.55-1.63 1000 ... 1.52-1.60 2000 ... 1.49-1.57 3000 ... 1.46-1.54 4000 ... 1.43-1.51 5000 ... 1.40-1.48 6000 ... 1.37-1.45 7000 ... 1.35-1.43

3) EGR Check. Disconnect and plug vacuum hose at EGR valve. Ensure that EGR valve is closed. Start or attempt to start engine. If symptom is eliminated or if no start is resolved, go to CIRCUIT TEST M, step 22). If symptom is NOT eliminated or if engine will NOT start, go to CIRCUIT TEST T, step 1).

TEST RR