CIS E Motronic Control Unit - New
Group: 25Number: 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"
^ display will appear as shown
^ press buttons 0 and 1 to select "ENGINE ELECTRONICS"
^ display will appear as shown
^ press Q button to enter input
^ display will appear as shown
^ press Q button to enter input
^ display will appear as shown
^ push right arrow button
^ display will appear as shown
^ push button 0 and 4 to select Function 04 "System in basic adjustment"
^ display will appear as shown
^ press Q button to enter input
^ display will appear as shown
^ press 0 button two times
^ display will appear as shown
^ press Q button to acknowledge input
^ display will appear as shown
Expanded Self-diagnosis: Function O8 "Read measuring value block"
When this function is selected:
^ The idle stabilization system and the carbon canister solenoid valve 1 are functioning.
^ Channel values are displayed over the entire RPM range.
^ Values for coolant temperature, RPM, etc. are displayed in the ten channels.
^ Channel 10 displays the ignition timing point as calculated by the control unit.
Note
An accurate Channel 10 display requires that the ignition timing point be properly adjusted (at the distributor).
Reading measuring value block with VAG 1551
^ push button 0 and 8 to select Function 08 "READ MEASURING VALUE BLOCK"
^ display will appear as shown
^ press 0 button to enter input
^ display will appear as shown
^ press 0 button two times
^ display will appear as shown
^ press Q button to enter input
^ display will appear as shown
Key to Function 04 and O8 channel display
Function O8/channel 9 display, interpreting
Channel 9 provides the technician with essential information that would have to be verified manually before performing the basic engine settings.
The ECU scans the system for certain conditions that must be met or for certain components that must be present or operative. It then assigns the numerical values (listed in the table) to these conditions or components and ADDS them together to create the display value.
A value of zero will be assigned to conditions or components in the chart that are NOT MET or NOT PRESENT.
Note
By analyzing the value displayed in channel 9 (using simple addition or subtraction) you can easily determine if a component or a condition is present or not.
See Figure for Example:
Ignition timing point, checking/adjusting
Checking
Requirement:
^ engine oil temperature 80~C (176~F) minimum
^ connect VAG 1367 engine tester using inductive pickup VAG 1367/8
CAUTION
Be sure TDC sensor is fully seated into transmission housing.
^ connect VAG 1551 diagnostic tester using adaptor cable VAG 155111 as follows
^ black terminal to black connector 1
^ white terminal to brown or white connector 2
^ blue terminal not used
^ start engine and let idle
^ observe VAG 1551 display value or "SYSTEM IN BASIC SETTING"
^ use the following codes to obtain the functions as shown
^ 1 to obtain "RAPID DATA TRANSFER" mode
^ 01 to select Function 01 "ENGINE ELECTRONICS"
^ 04 to select Function 04 "SYSTEM IN BASIC SETTING"
^ CO to select individual channel from group display
^ observe value displayed in channel 9
^ must be 5
If NO
^ see Function08/Channel 9 display, interpreting
Checking using VAG 1367 Engine tester
Timing point value is displayed directly on tester
^ checking value: 4 to 8~ Before TDO
Checking with timing light
^ direct strobe onto flywheel opening
^ checking value: 4 to 8~ Before TDC
Adjusting
^ adjust timing if necessary by loosening and turning distributor
^ adjusting value: 6 +/- 1~ Before TDC
If OK
^ enter O6 into VAG 1551 diagnostic tester for "DATA TRANSFER ENDED" input