Operation CHARM: Car repair manuals for everyone.
Home >> GMC >> 1993 >> Safari Van M V6-262 4.3L VIN Z >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Overvoltage Protection Relay >> Description and Operation
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Overvoltage Protection Relay: Description and Operation

PURPOSE
Inform the control module that there is a basic generator over voltage problem.

OPERATION

PCM/ECM
If voltage is greater than 19.5 volts for 2 seconds at PCM terminal "E16" (ECM is "C16"), the control module sets Diagnostic Trouble Code 53, the automatic transmission pressure control solenoid is turned "OFF", the automatic transmission shifts immediately to third gear, and TCC operation is inhibited. (the setting of additional DTC's may result.)

VCM
If voltage is greater than 17.1 volts at VCM terminal "GR2" sets Diagnostic Fault Code P1632. For 2 seconds after the fault is detected, the VCM will disengage its outputs. This may result in additional DTC's being set.


pro multis · About Operation CHARM