E/D7590

Fault Code E/D7590





Malfunction indicated
Safety system faulty

Fault symptom
The car goes into Limp Home mode. The TCS CTRL lamp lights up.

Note: With this fault code stored in the control unit's memory, the car will stay in Limp Home mode until the fault code is cleared using an SAT instrument.

Test procedure

1 If the fault code is generated at the same time as other fault codes, deal with the other fault codes first.

2 Clear the fault code. Switch the ignition off and on.Leave it on for at least five seconds and then switch it off again. Check whether the fault code is generated afresh.

3 With the ignition off, check that the throttle housing lever is retracted and the free play in the wire is at least 1 mm.

If not, check that the wire sheathing is in the correct position (lead-through in bulkhead partition) and that the adjusting screw is screwed in against its stop (M91 and early M92).




4 Connect a pressure gauge between the safety valve and the throttle housing vacuum chamber.
^ Start the engine and check that vacuum is created in the vacuum chamber.
^ Check that the butterfly lever leaves the throttle housing (the wire should be easy to press down-a slight degree of slackness)

5 Switch off the ignition and check that the vacuum is lost right away (approx.1-2 seconds).

If not, check that the hoses from the safety valve have free passage.

Note that most electrical faults which occur in the ETS system have the effect of disconnecting the safety valve. This makes it impossible to obtain a vacuum in the throttle housing vacuum chamber (Limp Home mode).




6 Enter command code 551 and check that the safety valve is working correctly by listening to it.

7 Start the engine to create a vacuum in the throttle housing again and then switch off the engine.

8 With a BOB connected, the ETS control unit unplugged and the ignition off, check that the lead between the safety valve and pin 35 of the control unit is not shorted to earth (the resistance across sockets 1 and 35 of the BOB should be OL).

9 Change the safety valve.

10 With the ignition switch in the Drive position, the wire disconnected from the throttle housing lever and the vacuum hose removed from the throttle housing, enter command code 208. The ISAT should then show 8B108 even when the accelerator is pressed to the floor.

If the ISAT display shows 8B008 and no faults have been found by following the above procedure, change the throttle housing.