4/26221, 4/26271

Fault Code 4/26221, 4/26271





Malfunction indicated
Temperature transmitter signal faulty or absent.

Fault symptom
Rough idling, poor driveablity.

Test procedure

1 Check that the control unit's connection to earth is OK.

2 Enter ISAT command code 250 and check that the instrument shows a rise in temperature during the engine's warm-up period.

3 With a BOB plugged into the ETS control unit connector (unplugged), check that the resistance across sockets 1 (earth) and 33 is correct for the current engine temperature.

4 If the reading is incorrect, measure the resistance directly at the temperature transmitter. If the reading here is also incorrect, change the temperature transmitter.








5 If the resistance reading is correct, check the YE lead between pin 2 of the temperature transmitter and pin 33 of the control unit for continuity or shorting to earth.

6 With a BOB plugged into the ETS control unit, all components connected and the ignition switch in the Drive position, check the voltage on socket 33 according to the table below.

Note: A reading of about 5 V indicates an open circuit, 0 V indicates a short to earth.

7 Clear the fault code and drive the car to see whether it is generated afresh. If it is, try fitting an ETS control unit that is known to be OK.