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.
1987 Cadillac SevilleFACTORY OEM SERVICE PROCEDURE
BCM Trouble Code-To-Circuit/Component Menu
ELDORADO & SEVILLE BCM TROUBLE CODES
| Code | Circuit Affected |
|---|---|
| B110 | Outside temp. sensor circuit |
| B111 | A/C High side temp. sensor circuit |
| B112 | A/C Low side temp. sensor circuit |
| B113 | In-car temp. sensor circuit |
| B115 | Sun-load temp. sensor circuit |
| B119 | Twilight photocell |
| B120 | Twilight delay pot |
| B121 | Twilight enable switch |
| B122 | Panel lamp dimming pot |
| B123 | Courtesy light switch |
| B124 | Vehicle speed sensor |
| B127 | PRND321 sensor |
| B128 | Bulb reference circuit |
| B334 | ECM data |
| B335 | CCDIC data |
| B336 | IPC data |
| B337 | Programmer data |
| B410 | Regulator |
| B411 | Battery low |
| B412 | Battery high |
| B420 | Relays |
| B440 | Air-mixture door |
| B441 | Cooling fans |
| B446 | Low refrigerant warning |
| B447 | Very low refrigerant problem |
| B448 | Low refrigerant pressure |
| B449 | A/C high temperature |
| B450 | Coolant high temperature (AC) |
| B550 | BCM memory reset |
| B556 | EE Prom |
| B660 | Cruise not in drive |
| B663 | Cruise speed difference |
| B664 | Cruise acceleration |
| B666 | Cruise RPM too high |
| B667 | Cruise switch shorted |
| B671 | Cruise position sensor |
| B672 | Cruise vent solenoid |
| B673 | Cruise vacuum solenoid |
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no 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.