Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1985 Buick Skylark Custom, 2.8 W, StandardFACTORY OEM SERVICE PROCEDURE
Trouble Code Component Identification
ECM TROUBLE CODE IDENTIFICATION
| Code | Circuit Affected | ||
|---|---|---|---|
| 12 | (1) | ||
| 13 | Open oxygen sensor circuit. | ||
| 14 | Coolant sensor circuit shorted. | ||
| 15 | Coolant sensor circuit open. | ||
| 21 | TPS signal voltage high. | ||
| 22 | TPS signal voltage low. | ||
| 23 | M/C solenoid circuit open or grounded. | ||
| 24 | VSS circuit. | ||
| 24B | Park/Neutral Switch. | ||
| 25 | MAT sensor signal voltage low. | ||
| 31 | Wastegate solenoid. | ||
| 32 | BARO sensor circuit. | ||
| " | EGR vacuum control (3.0L & 3.8L turbo). | ||
| 33 | MAP sensor voltage too high. | ||
| 33 | MAF sensor frequency high (Fuel Injection). | ||
| 34 | MAP sensor voltage too low. | ||
| 34 | MAF sensor frequency low (Fuel Injection). | ||
| 35 | ISC switch circuit shorted. | ||
| 41 | No distributor reference circuit. | ||
| 41 | C(3)I ignition (3.8L turbo). | ||
| 42 | EST circuit. | ||
| 42 | C(3)I ignition - cam sensor loss (3.8L turbo). | ||
| 43 | ESC retard signal too low. | ||
| 44 | Lean oxygen sensor value. | ||
| 45 | Rich oxygen sensor value. | ||
| 51 | Faulty PROM, PROM installation or ECM. | ||
| 52 | Faulty CALPAC. | ||
| 53 | EGR vacuum control (carb. models). | ||
| 54 | M/C solenoid high (carb. models). | ||
| 55 | Faulty ECM. | ||
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Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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