Powertrain, generic · Transmission
P0702 Transmission Control System Electrical
Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible
P0702 reports an electrical fault in the transmission control system as a whole – typically the supply of the transmission actuators (solenoid supply, transmission relay, supply switch in the module) or a circuit fault not assigned to a single component. No manufacturer document available to us describes it in detail; Ford's engine module list for 6.8 L E- and F-Series trucks stores it without the check engine light. If the solenoid supply is lost, transmissions usually fall back to a hydraulic limp gear. Individual solenoids have their own codes (P0750 ff); actuator supply is P0657 ff.
Likely causes
Transmission actuator supply interrupted (fuse, relay, ground)
Harness or connector at transmission or module damaged, corroded or oil-soaked
Transmission module output stage or supply switch faulty
Low or fluctuating system voltage
Symptoms
- Transmission limp mode with fixed gear
- Transmission warning; check engine light depending on the maker
- No or harsh shifts, further solenoid codes
Repair estimate
DifficultyMediumWorkshop job
Parts and labour€50–1,200
Time0.5–4 h
Typical range across vehicles; the real cost depends on what the testing finds.
Parts involved
transmission control moduletransmission solenoid supplytransmission wiring
Related codes
References: law.cornell.edu, roushcleantech.com.