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.
1986 Buick Riviera BaseFACTORY OEM SERVICE PROCEDURE
BCM System, Part II
- ECM Trouble Code Charts - Trouble Shooting
- Notes
- Code B110, Outside Temperature Sensor Circuit (TORONADO)
- Code B110, Outside Temperature Sensor Circuit (Riviera)
- Code B111, A/C High Side Temperature Sensor CKT (TORONADO)
- Code B111, A/C High Side Temperature Sensor Circuit (Riviera)
- Code B112, A/C Low Side Temperature Sensor Circuit (TORONADO)
- Code B112, A/C Low Side Temperature Sensor Circuit (Riviera)
- Code B113, In-Car Temperature Sensor Circuit (TORONADO)
- Code B113, In-Car Temperature Sensor Circuit (Riviera)
- Code B115, Sun Load Sensor Circuit (TORONADO)
- Code B115, Sun Load Sensor Circuit (Riviera)
- Code B118, Door Ajar/Jamb Switch Circuit (TORONADO Only)
- Code B119, Twilight Photocell Circuit (TORONADO)
- Code B119, Twilight Photocell Circuit (Riviera)
- Code B120, Twilight Delay Switch Pot Circuit (TORONADO)
- Code B120, Twilight Delay Switch Pot Circuit (Riviera)
- Code B120 & B122, Twilight Delay & Panel Dimming (TORONADO)
- Code B120 & B122, Twilight Delay & Panel Dimming (Riviera)
- Code B121, Twilight Enable Switch Circuit (Riviera Only)
- Code B122, Panel Dimming Switch Pot Circuit (TORONADO)
- Code B122, Panel Dimming Switch Pot Circuit (Riviera)
- Code B123, Courtesy Lights Panel Switch Circuit
- Code B124, Vehicle Speed Sensor (VSS) Circuit Problem
- Code B127, Gear Selector Switch Circuit (TORONADO Only)
- Code B131, Engine Oil Pressure Switch Circuit Problem
- Code B131 And/Or B132, Engine Oil Psi Sensor Circuit Problem
- Code B334, Loss Of ECM Serial Data (TORONADO)
- Code B334, Loss Of ECM Serial Data (Riviera)
- Code B335, Loss Of ECC Serial Data (TORONADO)
- Code B335, Loss Of ECC Serial Data (Riviera)
- Code B336, Loss Of IPC Serial Data (TORONADO)
- Code B336, Loss Of IPC Serial Data (Riviera)
- Code B337, Loss Of HVAC Programmer Data (TORONADO)
- Code B337, Loss Of HVAC Programmer Data (Riviera)
- Code B338, Loss Of Chime/Voice Serial Data (TORONADO Only)
- Code B339, Loss Of Radio Data (Riviera Only)
- Code B409, Charging System Problem (TORONADO)
- Code B409, Charging System Problem (Riviera)
- Code B410, Charging System Regulator Problem (Riviera Only)
- Code B411, Battery Voltage Too Low
- Code B412, Battery Voltage Too High
- Code B418, Crank Signal Circuit Problem (Riviera Only)
- Code B420, Relay Circuits (Riviera Only)
- Courtesy Light Relay Circuit (Riviera Only)
- Twilight Relays Circuit (Riviera Only)
- High/Low Beam Relays Circuit (Riviera Only)
- Retained Accessory Power Relays Circuit (Riviera Only)
- Code B440, HVAC - Air Mix Door Circuit Problem
- Code B445, A/C Compressor Engage Circuit
- CODE B445, A/C COMPRESSOR ENGAGE CIRCUIT (Cont.)
- Codes B446, B447 & B448 Low Refrigerant Pressure (TORONADO)
- Codes B446, B447 & B448 Low Refrigerant Pressure (Riviera)
- Chart A Codes B446, B447 & B448 Low Refrigerant Psi TORONADO
- Chart A Codes B446, B447 & B448 Low Refrigerant Psi Riviera
- Code B449, HVAC - High Side Temperature Too High
- Code B450, HVAC Coolant Temperature Too High
- Code B552, Keep Alive Memory Error (TORONADO)
- Code B552, BCM Keep Alive Memory Error (Riviera)
- Code B553, CRTC Keep Alive Memory Error (Riviera Only)
- Code B556, Odometer (Ee) Prom Error
- Code B660, Cruise Control Not In Drive (TORONADO)
- Code B660, Cruise Control Not In Drive (Riviera)
- Code B663, Cruise Speed Difference Between Actual And Set Too Large
- Code B664, Cruise Acceleration Too High
- Code B667, Set/Coast Or Resume/ACCEL Circuit Shorted
- Code B671, Cruise - Servo Position Sensor Circuit Problem
- Code B672, Cruise Vent Solenoid Circuit Problem
- Code B673, Cruise - Vacuum Solenoid Circuit Problem
- Code B710, CRT Switching Circuit Problem (Riviera Only)
- Multiple Intermittent Codes (Riviera Only)
- Notes
- Chart A - History Codes EO47, B334, B335, B336, B337
- Chart B - History Codes EO47 & B334
- Chart C - History Codes EO47 & B552
- Chart D - History Codes EO47, B334, B337
- Chart E - History Codes EO47, B334, B335, B337
- Chart F - History Codes B335, B336, B337
- Chart G - History Codes B335 & B336
- Chart H - History Codes B335 & B337
- Chart I - History Codes B335 & B553
- Chart J - History Codes EO047, B334, B335, B336, B337, B553
- Chart K - History Codes EO47, B552, B553
- Climate Control Diagnostic Charts
- Climate Control System Check (Riviera)
- Climate Control System Check (TORONADO)
- Chart 1, Codes 446,447,448 Low Refrigerant System (Riviera)
- Chart 1, Codes 446,447,448 Low Refrigerant (TORONADO)
- Chart A, Low Refrigerant Pressure Code 446,447,448 (Riviera)
- Chart A, Low Refrigerant Psi Code 446, 447 & 448 (TORONADO)
- Chart 2, Compressor Won't Engage (Riviera)
- Chart 2, Compressor Won't Engage (TORONADO)
- Chart 3, Compressor Always Engaged (Riviera)
- Chart 3, Compressor Always Engaged (TORONADO)
- Chart 4, Hi Blower Only (Riviera)
- Chart 4, Hi Blower Only (TORONADO)
- Chart 5, No Blower Operation (Riviera)
- Chart 5, No Blower Operation (TORONADO)
- Chart 6, Improper Air Delivery (Riviera)
- Chart 6, Improper Air Delivery (TORONADO)
- Chart 7, Insufficient Heat (Riviera)
- Chart 7, Insufficient Heat (TORONADO)
- Chart 8, Insufficient Cooling At Max Cool (Riviera)
- Chart 8, Insufficient Cooling (TORONADO)
- Chart 9, Improper Temperature Regulation (Riviera)
- Chart 9, Improper Temperature Regulation (TORONADO)
- Chart 10, A/C System Performance Test (Riviera)
- Chart 10, A/C System Performance Test (TORONADO)
- Chart 11, No "Def" From IP Switch (Riviera)
- Chart 11, Rear Defroster Inoperative (TORONADO)
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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