FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
Courtesy of Operation CHARM: Car repair manuals for everyone.

DTC 81 (Central Processing Unit)

ABS INDICATOR LIGHT "ON"

DIAGNOSIS - CPU DTC 81

DETECTION TIMING
Initial Diagnosis - yes
Except ABS Control - yes
During ABS Control - yes
During Warning - yes

PROBABLE CAUSE
- External factor(s) can be the cause(s) of the problem
- Faulty ABS control unit

CONDITION FOR DETECTION
The main CPU and sub CPU check each other under certain conditions. When the CPUs detect the following discrepancies, the ABS indicator light comes on.
- When there is discrepancy in the calculated wheel speed velocity that continues for more than a given period.
- When there is discrepancy in the phase information that continues for more than a given period.
- When there is discrepancy in the calculated control parameter.
- When the watch dog control pulse is fails for a given period.
- When the checksum of the ROM is fails.
- When there is discrepancy in the data reading and writing procedure of RAM.

MANAGEMENT
During ABS Control - System down
Except ABS Control - System down