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Porsche 944 User Manual

Page 153

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944 S/944 S2

Fuel System - Electronic Control

24/28

Fault, Fault Code

Possible Causes, Elimination, Remarks

Test

Point 15:

DME

relay

(fuel

pump) (V)

Start the engine - fuel pump must run during engine starting.

It not:

Turn off ignition. Disconnect control unit plug. Connect terminal 3 and terminal 24

on the control unit plug with help of a test lead.

Turn on ignition - the pump must run!

It not:

Check current flow and ground paths of DME relay and fuel pump according to the

wiring diagram.

Test

Point 16:

Tank

venting

valve (V)

Fault

Code

1_43

(not 944

S)

Electric valve (for brake booster) will be opened more or less long depending on

the engine load when an engine having operating temperature is running. The

opened time is determined by a ground pulse from the control unit.

a) Activation test

Activate the tank venting valve in the "element activation" menu of the tester. It a

pulse is not heard, check power supply to terminal 1 of the electromagnetic valve

plug according to the wiring diagram.

b) Control signal test

Install DME test read (Bosch No. 1 684 463 093) between the electromagnetic

valve and plug connection. Connect and adjust engine tester according to the

supplied operating instructions.

DME - Diagnosing/Troubleshooting

Printed In Germany - XXI, 1989

D 24/28 - 19