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.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSBUICK1987REGAL GRAND NATIONALREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCESYSTEM3.8L FEEDBACK CARBURETOR TESTS W/CODESECM TROUBLE CODE DEFINITIONS
1987 Buick Regal Grand National
ECM Trouble Code Definitions
1987 Buick Regal Grand NationalSECTION ECM Trouble Code Definitions
ECM TROUBLE CODE DEFINITION
| Code No. | Circuit Affected | ||
|---|---|---|---|
| 12 (1) | No RPM reference pulse. | ||
| 13 | Open oxygen sensor circuit. | ||
| 14 | Coolant sensor circuit shorted. | ||
| 15 | Coolant sensor circuit open. | ||
| 16 | System voltage high (3.8L "3800" VIN C). | ||
| 21 | TPS signal voltage high. | ||
| 22 | TPS signal voltage low. | ||
| 23 | MAT voltage high. | ||
| 23 | M/C solenoid voltage low. | ||
| 24 | VSS circuit. | ||
| 25 | MAT sensor signal voltage low. | ||
| 27, 28 & 29 | Gear switch problem (3.8L "3800" VIN C). | ||
| 31 | Purge sol. voltage high (carb.). | ||
| 31 | Park/Neutral switch (3.8L "3800" VIN C). | ||
| 32 | EGR vacuum control signal. | ||
| 32 | BARO voltage low (carb.). | ||
| 33 | MAP sensor voltage high. | ||
| 33 | MAF sensor frequency high (PFI). | ||
| 34 | MAP sensor voltage low. | ||
| 34 | VAC sensor circuit. | ||
| 34 | MAF sensor frequency low (PFI). | ||
| 35 | IAC (EFI) or ISC (carb.) speed error. | ||
| 38 | Brake switch (3.8L "3800" VIN C). | ||
| 39 | TCC (3.8L "3800" VIN C). | ||
| 41 | No distributor reference (HEI). | ||
| 41 | C(3)I ignition - cam sensor loss. | ||
| 41 | Cylinder select error (MEM-CAL). | ||
| 42 | EST circuit open or grounded. | ||
| 43 | ESC retard signal too low. | ||
| 44 | Lean oxygen sensor value. | ||
| 45 | Rich oxygen sensor value. | ||
| 48 | Misfire (3.8L "3800" VIN C) | ||
| 51 | Faulty PROM, MEM-CAL or ECM. | ||
| 52 | Faulty/missing CALPAC or MEM-CAL. | ||
| 53 | Faulty alternator, voltage high. | ||
| 54 | Fuel pump voltage low. | ||
| 55 | Faulty ECM. | ||
| 63 | EGR flow error (3.8L "3800" VIN C). | ||
| 64 | EGR flow error (3.8L "3800" VIN C). | ||
| 65 | EGR flow error (3.8L "3800" VIN C). | ||
|
|||
NOTE:
Trouble code charts should only be used if "SERVICE ENGINE SOON" light is illuminated (indicating a current problem exists). Exceptions are Code 13, 15, 24, 44 and 45 charts, which may be used to help diagnose intermittent codes.
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.