Transmission Control System
CODE NUMBERScan tool: 14
General scan tool: P1767
CODE NAME
Relay always on (Relay contacts are welded closed)
CODE DESCRIPTION
Technical Description
The Transmission Control relay is used to supply power to the solenoid pack when the transmission is in normal operating mode. When the relay is off, no power is supplied to the solenoid pack and the transmission is in "limp-in" mode. The relay output is fed back to the TCM through pins 56 and 57.
Check Area
Ignition key is turned from "off" position to "run" position and/or ignition key is turned from "crank" position to "run" position. The following conditions must be met for a successful OBD II trip:
- The engine must run for more than two minutes
- The turbine speed must be greater than 600 r/min or the output speed must be greater than 400 r/min
- If the transmission is below normal operating temperature, all forward gears must be applied for 3.5 seconds each and the transmission must be in either "park" or "neutral" for 3.5 seconds.
- If the transmission is hot, all forward gears must be applied for 1.5 seconds each and the transmission must be in either "park" or neutral" for 1.5 seconds.
- No MIL lamp trouble codes have occurred or recurred.
Set Conditions
This code is set if the Transmission Control Module (TCM) sense is greater than 3 volts at the Transmission Control Relay Output terminals of the TCM prior to the TCM energizing the relay.
Transmission Effects
Logical limp-in mode. The TCM will put the transmission in 2nd gear and not allow it to shift.
PROBABLE CAUSE
- Malfunction of relay (welded contacts)
- Short to power on control side of relay between relay and TCM
- Short to power on load side of relay between relay and TCM
- TCM relay driver circuit stuck ON
DIAGNOSTIC CHART