CODE 53 - System Over Voltage
Trouble Code 53 refers to a feature never actually installed on any turbo Regal. This code was reserved when these vehicles where being developed, in the event that water injection hardware would be installed in production vehicles.
Since water injection was never actually used, this code should never appear.
Typical causes for this code include:
1) Incorrect PROM installed in the ECM
2) PROM incorrectly installed in the ECM
3) Defective PROM
Some after market PROMs, particularly those designed as 'off road use only', may not properly deal with trouble codes. If it is suspected this is causing a Code 53, contact the PROM manufacturer.