Passat L4-1984cc 2.0L DOHC (9A) (1990)
Engine Control Module: All Technical Service Bulletins
CIS E Motronic Control Unit - New
Group: 25
Number: 91-01
Date: March 1, 1991
Subject:
New control unit for vehicles with CIS-E Motronic systems
Model(s):
Passat, Jetta , GTI w/9A engine
1990-1991 m.y.
A - New CIS-E Motronic control unit with expanded features
Starting in October 1990 production, a new CIS-E Motronic control unit was installed as a running change.
^ Part Number:
(49 State) 8A0 907 404
(California) 893 907 404Q
Note
The control unit part number is displayed on the VAG 1551 (as it always has) during activation.
The new control unit differs from the old one as follows:
1 - Expanded self-diagnosis now includes:
^ Function 04 "System in basic setting"
^ Function 08 "Read measuring value block"
2 - The ignition portion of the system is now equipped with Digital idle stabilization.
Note
Ignition timing can now be monitored via the VAG 1551 in Function 08.
B - For Passat vehicles with 4-speed automatic transmissions:
If the throttle switch/potentiometer is replaced on a vehicle with an automatic transmission
^ activate VAG 1551 diagnostic tester to return the automatic transmission control unit to the "O4 Basic setting"
A - Expanded Self-diagnosis: Function O4 "System in Basic setting"
^ When Function O4 is selected (via the VAG 1551) the idle stabilization system is switched off and the carbon canister solenoid valve is closed.
^ values for coolant temperature, RPM, etc. are then displayed in the ten channels.
Note
The channel values are displayed up to a maximum of 2000 RPM after which the channels go to zero.
Engine basic setting adjustment using the VAG 1551
^ connect VAG 1551 diagnostic tester, see section D2-30 of Repair Group D2 for additional information
^ switch ON ignition
^ press button 1 to select operating mode "Rapid data transfer"