VARIOUS DRIVEABILTY CONDITIONS (REPAIR OVERSIZED TERMINALS)

SUBJECT: VARIOUS DRIVEABIUTY CONDITIONS (REPAIR OVERSIZED TERMINALS)

MODELS: 1992 C/K TRUCKS AND M/L AND G VANS

CONDITION:

---------- Some owners of the vehicles listed below may experience various driveability conditions such as reduced fuel economy, SES light, runs rough, misses, etc. (specific concerns are described in the following paragraphs). If diagnosis indicates a need to replace any control system components (example, ECM or sensors), check suspect connector terminals and repair if necessary prior to replacing the control system component.

CAUSE:

------ The condition may be a result of intermittent or open circuits caused by insufficient contact between the ECM harness female terminal and the mating ECM male pin. Some of the 12089649 micro-pack 100 series female terminals (formerly P/N 12020757) could have an oversized contact area condition. NOTE: Either terminal may be used in repair.

VIN BREAKPOINTS:

Suspect vehicle VIN breakpoints for TRUCKS follow: Name Beginning VIN Ending VIN Plate ------------- ----------- ----- Oshawa ------ 2GTEC19K7N1540187 12GTEC19K2N1541957 GMC

Pontiac East

1GTEC14H1NE529454 1GETK14Z9NE534123 GMC 1GTEC14K0NE536004 1GTDC14Z2NE536353 GMC

Fort Wayne

1GTDC14Z0NZ529877 1GTEC14H4NZ531286 GMC

Baltimore

1GKDL15W1NB527573 1GKEL19W1NB534456 GMC

Scarborough

2GTGG39K8N4515208 2GDHG31K3N4522546 GMC

Lordstown

1GTEG25Z7N7510624 1GKEG25KXN7513752 GMC

SYMPTOMS(Trucks):

Refer to SYMPTOMS (Trucks) Chart attached.

CORRECTION:

----------- 1. To check for an oversize terminal, use a #62* drill bit (.038 inches, .965 mm) and place a mark 1/2 inch up from the bottom of the shank of the drill bit. Place a flag made from tape at the mark on the drill (see Figure 1).

2. Remove connector from ECM and hold connector vertically up.

3. Place shank of #62* drill bit (.038 inches, .965 mm) in connector cavity of suspect terminal. Do not push on drill (see Figure 2).

4. Repair any terminal allowing drill bit to fall unassisted to the flag on drill bit. Any terminals having resistance or drag or not allowing drill to enter terminal are okay and do not need repair. Repair any oversized terminal as described in steps 5 through 8.

5. Remove the TPA (terminal position assurance) from the connector.

6. Remove the terminal from the connector using terminal removal tool GM 12031876-1 (Kent-Moore Tool No. J 38125-A).

7. With a pair of small needle nose pliers, resize the contact area of the terminal as shown in Figure 3.

8. To verify the terminal has been adequately sized, insert a #63* drill bit (.037 inches, .0940 mm) into the contact area as shown in Figure 4. If resistance can be felt against the bit in the resized area, resizing is complete. If no resistance is felt, repeat steps 7 and 8.

9. Raise the terminal lock tang (Figure 4) so the terminal can properly held in the connector.

10. Reinsert the terminal into the proper connector cavity.

11. Reinsert the TPA into the connector.

12. If the terminal becomes severely damaged by using this method, replace the terminal using established terminal replacement procedures.

13. Reinstall harness to ECM and perform any required relearn procedure prior to continuing diagnosis.

*NOTICE: Measure drill to ensure drill is of proper diameter. A larger sized drill will damage a good terminal.

WARRANTY INFORMATION:

Use applicable labor operation and time allowances.

SYMPTOMS (Trucks)

Connector Cavity/ Engine Options Circuit(s) Wire Color Symptom(s) ------ ------- ---------- ---------- ---------- 1992 C/K Trucks (Regular or Extended Cab) GVW less than 7200 lbs. ------------------------- 5.0L (L03) MG5/MT8 413 D6/TAN 1. SES light "on" 5.7L (L05) Man tran O2sensor 2. Code 13 stored ground 3. Stalling 4. Detonation 5. Surge 6. Hesitates 1992 C/K Trucks (Regular or Extended Cab) 7. Engine runs rough All Series 8. Intermittent circuit --------------- may or may not set 5.0L (L03) MD8-4L60 413 D6/TAN code 13 trans O2sensor 9. Erratic engine ground operation 10. Intermittent circuit will cause erratic Tech 1 readings

1992 C/K Trucks (Regular or Extended Cab) 10 & 20 Series --------------- 5.7L (L05) MD8-4L60 413 D6/TAN trans O2sensor ground

1992 C/K Trucks (Regular, Extended, Or Crew Cab) 8600 GVW & over ---------------- 5.7L (L05) MT8 413 D6/TAN Man tran O2sensor ground ------------------------------------------------------------------------------ 1992 M/L VAN ------------ 4.3L (L35) All 120 B2/GRY 1. SES light 'on' Fuel pump 2. Code 54 stored signal 3. Intermittent circuit will cause erratic Tech 1 readings ------------------------------------------------------------------------------ 4.3L (L35) All *450 A12/BLK 1. Erratic engine Ground operation 2. Stalling 3. Surge 4. Flickering SES light *The terminals for system ground 5. No codes stored circuits 450 and 551 must both be 6. No start replaced on M/L vans if any one of 7. Quit the ground terminals is found faulty. 8. Hesitates Use established replacement procedures. 9. Poor fuel economy 10. Hard start 11. Intermittent circuit will cause erratic Tech 1 readings ------------------------------------------------------------------------------ 1992 G Van ---------- 5.0L (L03) MD8-4L60 *450 D1/BLK/WHT 1. Poor fuel economy 5.7L (L05) Trans System 2. Erratic engine ground operation 3. Stalls 4. No start 5.7L (L05) MT1-4L80E *551 C3/Tan/WHT 5. Quit JA4 *450 C2/BLK/WHT 6. Hard start 92C (SEO) 7. Flickering SES light 8. No codes stored 9. Hesitates *The terminals for system ground 10. Surge circuits 450 and 551 must both be 11. Intermittent circuit replaced on G vans if any one of will cause erratic the ground terminals is found faulty. Tech 1 readings Use established replacement procedures. ------------------------------------------------------------------------------ 5.0L (L03) MD8-4L60 441 C5/LtBLU/WHT 1. Stalls 5.7L (L05) JA4 IAC 'A' Hi 2. Low or high idle 3. Intermittent circuit 5.7L (L05) MT1-4L80E 441 could cause JA4 IAC 'A' Hi erratic idle ------------------------------------------------------------------------------ 5.0L (L03) MD8-4L60 437 A10/BRN 1. SES light "on" 5.7L (L05) JA4 VSS 2. Code 24 stored 3. Unstable idle 4. Intermittent circuit may or may not set code 24 5. No TCC 6. Poor fuel economy 7. Intermittent circuit will cause erratic Tech 1 readings ------------------------------------------------------------------------------ 5.7L (L05) MT1-4L80E 437 B11/BRN 1. SES light "on' JA4 VSS 2. Code 24 stored 3. No shift beyond 2nd 4. Intermittent circuit will cause erratic Tech 1 readings ------------------------------------------------------------------------------ 5.7L (L05) MT1-4L80E 496 D5/DkBLU 1. SES light "on" JA4 ESC (knock) 2. Code 43 stored signal 3. Spark knock 4. Intermittent circuit may or may not set code 43 ------------------------------------------------------------------------------ 5.7L (L05) MD8 467 D16/BLU 1. Detonation 4L60 Injector 1 2. No power 3. Hard start 4. Rough idle 5. SES light "on" 6. Code 43 and/or 44 stored 7. Miss 8. Hesitates 9. Surge 10. Quit 11. Intermittent circuit may or may not set codes ------------------------------------------------------------------------------ 5.7L (L05) MT1-4L80E 435 A11/GRY 1. SES light "on' JA4 EVRV(EGR) 2. Code 32 stored control 3. Rough idle 4. Poor fuel economy 5. Hesitates 6. Stall at idle 7. Intermittent circuit may or may not set code 32 ------------------------------------------------------------------------------ 5.7L (L05) MT1-4L80E 420 A12/PPL 1. No TCC JA4 Brake signal 2. No shift to 4th gear 3. Poor fuel economy 4. Intermittent circuit will cause erratic Tech 1 readings ------------------------------------------------------------------------------ 4.3L (LB4) MT8-4L60 452 A11/BLK 1. SES light "on" JA4 CTS & TPS 2. Codes 15 and/or 21 sensor and/or 45 stored ground 3. High idle 4. Poor fuel economy 5. Engine runs rich 6. Hard start 7. Hesitates 8. Surges 9. Stall 10. No power 11. Exhaust odor 12. Intermittent circuit may or may not set codes 13. Intermittent circuit will cause erratic Tech 1 readings

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.