How is fault code P0702 fixed?

A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training. 1. Pull every stored code along with the freeze-frame data. P0702 rarely travels alone, and the partner code is what actually tells you where to look. Fix that and P0702 usually clears with it 2. Check for manufacturer service bulletins on your model, plenty of makes have known wiring or connector issues that point you straight to the fault 3. Get the car on a ramp and inspect the transmission looms and plugs for chafing, corrosion, bent pins or water sitting in a connector. This finds more P0702 faults than any module test 4. Check the gearbox fluid level and condition, top up if low and look hard at burnt or contaminated fluid because dirty fluid upsets the internal sensors 5. Measure battery voltage and the TCM power and earth circuits with a multimeter, looking for voltage drop under load or high resistance on the grounds 6. Only once wiring, fluid and grounds check out should you start suspecting the TCM or PCM, and that's a job for proper dealer-level diagnostics

Transmission Control System Electrical

Jump to the fix

Severity

High

Can I keep driving?

Avoid extended driving; visit a service soon.

First step

A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training. 1. Pull every stored code along with the freeze-frame data. P0702 rarely travels alone, and the partner code is what actually tells you where to look. Fix that and P0702 usually clears with it 2.

PPowertrain
0Generic code
7Transmission
02Sequence number

What does it mean?

If you think about it, the modern automatic transmission does everything that a manual transmission does, modulating throttle position, clutch position, and gear position, all on its own, and the brains of the operation is the TCM (transmission control module). The TCM uses a number of actuators, such as solenoids and pressure regulators, to shift into different gears, depending on vehicle speed and driver demand. The TCM also uses feedback from a number of sensors to verify proper operation.

If a fault is detected, such as shaft revolutions out of range for a specific gear position, a DTC (diagnostic trouble code) will be set in memory. The ECM (engine control module), which is in constant communication with the TCM, will also set a DTC, referencing the TCM, and illuminate the MIL or CEL (malfunction indicator lamp or check engine light).

DTC P0702 refers to a general transmission control system electrical fault, but not to a specific fault, such as a solenoid open circuit, for example. On finding DTC P0702 stored in ECM memory, further diagnosis will be required to determine the nature of the fault.

Symptoms

Likely causes

How to fix it

Codes From the Same System

All Fault Codes

Related Similar Codes

This information follows the generic OBD-II definition and does not replace a vehicle-specific diagnosis. The severity rating is rule-based; an authorised diagnostic reading is required for a definitive answer.