CODE B450, COOLANT TEMPERATURE TOO HIGH Buick Riviera VII

CODE B450, COOLANT TEMPERATURE TOO HIGH

Code B450 is designed to disengage A/C compressor clutch if engine coolant temperature exceeds 261°F (126°C) and re-engage clutch when coolant temperature falls to less than 120°C. If Code EO14 is also stored, follow diagnosis for that code first. Engine overheating may accompany this code. If coolant temperature exceeds normal operating range, check for sources of overheating. Carefully check all sources of intermittent engine overheating, such as improper coolant fan operation, faulty belt or tension, low coolant level and restrictions or faulty hoses and/or routings.

Code B482, Wiring Diagram Anti-Lock Pressure Problem. Scheme 189

This code indicates that brake pressure switch has indicated a low pressure condition to BCM. If Code B482 is set, and you are experiencing braking problems, diagnose ABS and normal braking system. Code B482 sets whenever circuit No. 933 is pulled low to ground and remains low for 50 seconds. As soon as circuit No. 933 goes low, the Red "Brake" telltale will illuminate. The warning message on the Digital Instrument Cluster (DIC) for "Low Brake Pressure" will not illuminate until after 50 seconds. The amber "Anti-Lock" telltale in the IPC is controlled only by ABS control unit.

If this code is set as "History" and you are not experienced braking problems, look for a short to ground in circuit No. 933. Shorted conditions would have to be present for at least 50 seconds.

Code B552, Wiring Diagram BCM Keep Alive Memory Error. Scheme 190

Code B552 does not necessarily indicate a fault, but is a normal occurrence anytime battery power or ground to BCM has been interrupted. Code B552 cannot be cleared from memory in the normal manner. Code B552 can only be cleared if it is not current. Under normal conditions, code will become "History" under the following conditions

1. Ignition in lock position.
2. Wait for 5 seconds.
3. Ignition key on, re-enter diagnosis.

After the above conditions have taken place, code should now be "History", and can be cleared in the normal manner. This code could be set if the system voltage drops to less than 8 volts at BCM terminal No. 1C9. Possible causes for this are faulty charging system, starter system, extreme cold weather and jump starting vehicle.

Note. Test numbers refer to numbers on diagnostic chart.

1. This step is to change Code B552 from "Current" to "History".
2. Checks to see if Code B552 was set due to a fault during cranking mode.
3. Checks for adequate system voltage at BCM terminal No. 1C10. System voltage must not drop to less than 8 volts during engine cranking. By removing fuel pump fuse, engine will not start and voltage during engine cranking can be observed.

Code B552, Flow Chart BCM Keep Alive Memory Error. Scheme 191

Code C553, Wiring Diagram CRT Keep Alive Memory Error (Reatta & Riviera). Scheme 192

Code C553 does not necessarily indicate a fault, but is a normal occurrence anytime the power to CRTC has been interrupted. This code could set if the system voltage drops to less than 8 volts at CRT terminal "C1". Possible causes are faulty charging system, starter system, extreme cold weather or jump starting vehicle.