Diagnosis of Electrical Components and Reading Fault Codes

GENERAL INFORMATION

The electronic transmission control system consists of the control unit (TCM), located under the rear seat, shift solenoids, various sensors and sensor switches.

If the TCM detects faults in the control circuits, it stores them in memory. To read the codes, use electronic tester VAG 1551 with adapter VAG 1551/3.

Note: All information on reading codes is contained in the tester.

Alternatively, faults can be detected by measuring resistance and voltage values using tester VAG 1598/18 (refer to the tables).

Voltage checks are performed without disconnecting the battery. Connect the tester to the TCM and its wiring. When checking resistance, disconnect the negative battery cable and connect the tester to the TCM wiring harness. Leave the TCM disconnected.

If a fault is detected, repair the wiring or the relevant circuit component. If everything is in order, the TCM itself is faulty.

Voltage and resistance checks to identify faults in electrical components

Voltage and resistance checks to identify faults in electrical components

VAG fault code list for the transmission control system

00258 Open circuit, short to ground or damage to solenoid 1 00260 Open circuit, short to ground or damage to solenoid 2 00262 Open circuit, short to ground or damage to solenoid 3 00264 Open circuit, short to ground or damage to solenoid 4 00266 Open circuit, short to ground or damage to solenoid 5 00268 Open circuit, short to ground or damage to solenoid 6 00270 Open circuit, short to ground or damage to solenoid 7 00281 Open circuit in wiring, vehicle speed sensor or wheel sensor faulty 00293 Open circuit in wiring or faulty transmission mode switch sensor 00297 Open circuit in wiring or faulty speed sensor 00300 Open circuit in wiring or faulty ATF temperature sensor 00518 Open/short in wiring or faulty throttle position sensor (throttle position sensor signal is sent to the TCM via the ECM; on vehicles with CAN bus the TCM only checks that the sensor signal is received, on models without CAN bus the condition of the signal wire is also checked) 00529 Open circuit in wiring or loss of signal from vehicle speed sensor, transmission output speed sensor, engine speed or throttle position sensor 00532 Low supply voltage to solenoid valves due to battery discharge 00545 Open circuit in wiring or short to ground (communication between engine and transmission control modules is interrupted) 00596 Short circuit in solenoid valve wiring 00638 Open circuit in wiring or short to ground (communication between engine and transmission control modules is interrupted) 00641 Excessively high ATF temperature or faulty ATF temperature sensor 00652 Electrical or hydraulic malfunction (clutch or valve body assembly) 00660 Open circuit in wiring or incorrect connection of throttle position sensor (sensor faulty) 65535 TCM faulty