Data Communication System: Other Saturn Astra I

Circuit/System Verification

If this DTC is retrieved as a current DTC, replace the module that set the DTC.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for module replacement, setup, and programming

Reference Information

Schematic Reference

Data Communication Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Data Link Communications Description and Operation

Electrical Information Reference

1. «Circuit Testing»(ref-302317-S14465820352008102100000)
2. «Connector Repairs»(ref-302317-S07938571952008102100000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-302317-S07813738172008102100000)
4. «Wiring Repairs»(ref-302317-S36649915442008102100000)

Scan Tool References

Control Module References for scan tool information

1. Verify DTC B1001 is not set. If the DTC is set, program the control module.
2. With a scan tool, clear the DTCs.
3. Ignition OFF, remove the scan tool, open and close the drivers door.
4. Wait 60 seconds, then verify DTC B1001 is not set. If the DTC is set, replace the control module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for control module replacement, setup, and programming

1. Program the VIN information to the module that set the DTC.
2. Turn the ignition OFF, wait several seconds and then turn the ignition ON.
3. Retrieve DTCs from the module that set the DTC. DTC B1016 should change to a history DTC. If this DTC is retrieved as a current DTC, replace the module that set the DTC.

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for BCM replacement, setup, and programming

Schematic Reference

1. «Data Communication Schematics»(ref-302336-S19795656812008102100000)
2. «Control Module References»(ref-302291-S24032387652008102100000)

Connector End View Reference

Component Connector End Views

Description and Operation

Data Link Communications Description and Operation

Electrical Information Reference

1. «Circuit Testing»(ref-302317-S14465820352008102100000)
2. «Connector Repairs»(ref-302317-S07938571952008102100000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-302317-S07813738172008102100000)
4. «Wiring Repairs»(ref-302317-S36649915442008102100000)

Scan Tool Reference

Control Module References for scan tool information

1. Verify that following BCM DTCs are not present: U1814 U2099 B1428 B1370 B1380 B1440 B1441 If any listed DTC is present, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(ref-302315-S34223864312008102100000) to diagnose that DTC prior to this diagnostic.
2. Verify that at least 1 module that communicates on high speed GMLAN serial data communicates with the scan tool. If no module communicates on high speed GMLAN serial data, refer to «Scan Tool Does Not Communicate with High Speed GMLAN Device»(ref-302336-S04067115332008102100000) .
3. Verify that at least 1 module, excluding BCM, that communicates on low speed GMLAN serial data communicates with the scan tool. If no module communicates on low speed GMLAN serial data, excluding BCM, refer to «Scan Tool Does Not Communicate with Low Speed GMLAN Device»(ref-302336-S10382331312008102100000) .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «GMLAN Wiring Repairs»(ref-302317-S26872416132008102100000)
2. «Control Module References»(ref-302291-S24032387652008102100000) for module replacement, setup, and programming

Action Taken When the DTCs Sets

1. The module suspends all message transmission.
2. The module uses default values for all parameters received on the serial data circuits.
3. The module inhibits the setting of all other communication DTCs.

1. Refer to «Data Link References»(ref-302336-S15031585792008102100000) to determine which serial data system is used for a specific module.
2. This DTC cannot be retrieved with a current status. Diagnosis is accomplished using the symptom «Scan Tool Does Not Communicate with High Speed GMLAN Device»(ref-302336-S04067115332008102100000) or «Scan Tool Does Not Communicate with Low Speed GMLAN Device»(ref-302336-S10382331312008102100000) .

1. Verify DTC P0606 is not set as current. If DTC is set, replace the ignition coil.
2. With a scan tool, clear DTC's, and verify DTC P0606 is not set as current. If DTC is set, replace the ECM.
3. Verify DTC U2101 is not set as current. If DTC is set, replace the control module that set U2101.

1. «Data Communication Schematics»(ref-302336-S19795656812008102100000)
2. «Control Module References»(ref-302291-S24032387652008102100000)

Connector End View Reference

Component Connector End Views

Description and Operation

Data Link Communications Description and Operation

Electrical Information Reference

1. «Circuit Testing»(ref-302317-S14465820352008102100000)
2. «Connector Repairs»(ref-302317-S07938571952008102100000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-302317-S07813738172008102100000)
4. «Wiring Repairs»(ref-302317-S36649915442008102100000)

Scan Tool References

Control Module References for scan tool information

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «GMLAN Wiring Repairs»(ref-302317-S26872416132008102100000)
2. «Control Module References»(ref-302291-S24032387652008102100000) for module replacement, setup, and programming

Symptoms - Data Communications

1. Perform the «Diagnostic System Check - Vehicle»(ref-302315-S22962940552008102100000) before using the symptom tables in order to verify that all of the following are true: There are no DTCs set. The control modules can communicate via the serial data links.
2. Review the system operation in order to familiarize yourself with the system functions. Refer to «Data Link Communications Description and Operation»(ref-302336-S27588655162008102100000) .

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Schematic Reference

Data Communication Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Data Link Communications Description and Operation

Electrical Information Reference

1. «Circuit Testing»(ref-302317-S14465820352008102100000)
2. «Connector Repairs»(ref-302317-S07938571952008102100000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-302317-S07813738172008102100000)
4. «Wiring Repairs»(ref-302317-S36649915442008102100000)

Scan Tool Reference

Control Module References for scan tool information.

Perform the Diagnostic Repair Verification after completing the repair.

Schematic Reference

Data Communication Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Data Link Communications Description and Operation

Electrical Information Reference

1. «Circuit Testing»(ref-302317-S14465820352008102100000)
2. «Connector Repairs»(ref-302317-S07938571952008102100000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-302317-S07813738172008102100000)
4. «Wiring Repairs»(ref-302317-S36649915442008102100000)

Scan Tool Reference

Control Module References for scan tool information.

Attempt to communicate with all modules on the high speed GMLAN bus.

1. If any high speed module communicates and any DTC beginning with a U exists, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(ref-302315-S34223864312008102100000) .
2. If any high speed module communicates and no DTC beginning with a U exists, refer to «DTC U2105-U2199»(ref-302336-S19719217352008102100000) .

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for control module replacement, setup, and programming

GMLAN Wiring Repairs

Schematic Reference

Data Communication Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Data Link Communications Description and Operation

Electrical Information Reference

1. «Circuit Testing»(ref-302317-S14465820352008102100000)
2. «Connector Repairs»(ref-302317-S07938571952008102100000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-302317-S07813738172008102100000)
4. «Wiring Repairs»(ref-302317-S36649915442008102100000)

Scan Tool Reference

Control Module References for scan tool information.

Attempt to communicate with all modules on the mid speed GMLAN bus.

1. If any high speed module communicates and any DTC beginning with a U exists, refer to «Diagnostic Trouble Code (DTC) List - Vehicle»(ref-302315-S34223864312008102100000) .
2. If any high speed module communicates and no DTC beginning with a U exists, refer to «DTC U2105-U2199»(ref-302336-S19719217352008102100000) .

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for control module replacement, setup, and programming

GMLAN Wiring Repairs

Schematic Reference

Data Communication Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Data Link Communications Description and Operation

Electrical Information Reference

1. «Circuit Testing»(ref-302317-S14465820352008102100000)
2. «Connector Repairs»(ref-302317-S07938571952008102100000)
3. «Testing for Intermittent Conditions and Poor Connections»(ref-302317-S07813738172008102100000)
4. «Wiring Repairs»(ref-302317-S36649915442008102100000)

Scan Tool Reference

Control Module References for scan tool information.

Perform the Diagnostic Repair Verification after completing the repair.

1. «Control Module References»(ref-302291-S24032387652008102100000) for module replacement, setup, and programming
2. «GMLAN Wiring Repairs»(ref-302317-S26872416132008102100000)

Data Link References

The scan tool Low Speed CAN-Bus Config, Mid Speed CAN-Bus Config, and High Speed CAN-Bus Config functions as used to determine which modules are communicating on each buss. Before using these functions, ensure you can communicate with modules on each buss and that no DTCs in the DTC U2105-U2199 range exist. If you can not communicate with any module on a particular buss you must resolve this issue before using these functions. If you have DTC's in the DTC U2105-U2199 range you can use these functions as an aid to determine what module is no longer communicating on the buss. Some modules may use more than one data link to communicate. Some modules may have multiple communication circuits passing through them without actively communicating on that data link. This function is used to assist in correcting a communication malfunction. For the description and operation of these serial data communication circuits refer to Data Link Communications Description and Operation .

Rear electrical center (REC)

The Rear Electrical Center (REC) is a central module and is located in the luggage compartment on the left-hand side, behind the service flap. It contains a fuse and relay box and a control unit which communicates with the other bus users via the LS CAN bus. The REC controls, amongst other things, the rear lighting, the rear window wiper, the central locking and the electric windows. Various sensors (e.g. tank fill level) are read in and their values output as bus messages by the REC.

The following functions are actuated depending on the corresponding signal input

1. Electric windows function (the REC is the function master for the electric windows. It actuates all servo motors in the doors directly).
2. Alarm system function (the REC communicates via a serial UART interface with the ultrasonic alarm system or with the alarm siren).

Other functions

1. Tank fill level, the REC reads in the value from the tank fill level sensor and transmits this on the bus.
2. Trailer module; a trailer module can be connected to the REC. The wiring harness for the trailer coupling is then connected to this. If the REC detects that a trailer is actually connected, it sends a corresponding message on the bus, actuates the lights on the trailer and will also monitor the bulbs in the trailer lighting. However, the rear fog lamp and the reversing light of the trailer will not be monitored, as most commercially-available trailers are not fitted with this function.

SCCM

The steering column control module (SCCM) is the module on the steering column which, amongst other things, contains the ignition lock and the turn signal and wiper switches. It combines the following sub-systems (some of which are optional).

Immobilizer, steering wheel controls, transponder aerial, ignition lock, turn signal stalk, main/dipped beam stalk, cruise control stalk, Info Display buttons, windscreen wiper stalk, radio receiver for the key remote control, steering angle sensor, horn button, PEPS start button (passive entry passive start system) and ESCL (electric steering column lock). The SCCM has been developed to reduce the complexity of the wiring and reduce the weight of the steering column.

SCCM Control Unit

The steering column control module (SCCM) control unit has two CAN interfaces, one to the low-speed CAN bus and one to the high-speed CAN bus. It is used as the interface between the high-speed bus and the low-speed bus to exchange information between the CAN buses. All components of the SCCM, except the ignition key with its RF receiver/transmitter (transponder), are directly connected to the SCCM control unit (plug connection) and therefore require no additional wiring.

Voltage Management, Voltage Supply, Ignition Lock

The SCCM control unit is responsible for voltage management within the vehicle. It is responsible for decoding the ignition lock information (ignition key position) and for forwarding this information as CAN information to the rest of the vehicle. In addition, the SCCM actuates, by hard wiring, two power supply relays in the UEC and REC. The ACC (ignition lock position 1) signal is also transmitted by hard wire to the ECM to power it up more quickly. The engine will fire more quickly as a result.

Bus Interface to the High-Speed CAN (HS CAN) and Low-Speed CAN (LS CAN)

1. The SCCM has two CAN interfaces for data communication.
2. High-speed CAN for engine systems, drive train systems, immobilizer, etc.
3. Single wire low-speed CAN for body systems.
4. Interface between HS CAN and LS CAN.
5. The SCCM is the interface (transfer point) between the low-speed bus and the high-speed bus. Selected bus messages are transferred from the low-speed bus to the high-speed bus and vice versa.

Dimming the Steering Wheel Controls Illumination

The buttons for the steering wheel controls are illuminated. This illumination is dimmed in response to information which is transmitted by the IPC to the SCCM via the LS CAN.

Turn Signals Function

The SCCM control unit records 4 positions of the turn signal stalk in digital form. The turn signal stalk no longer engages mechanically and instead returns to its initial position, even when the turn signals are switched on. They are switched off either by the steering angle sensor or by moving the stalk in the opposite direction. This information is transmitted by the SCCM control unit via the LS CAN to the REC which then specifies the flash frequency and the duty factor.

Cruise Control Function

The SCCM control unit records the 3 positions of the cruise control switch in digital form. This information is transmitted by the SCCM control unit to the engine control module (ECM) control unit via the HS CAN.

Windscreen Wiper Function

The SCCM control unit records the 6 positions of the windscreen wiper stalk in digital form. This information is transmitted by the SCCM control unit to the UEC control unit via the LS CAN. The wiper stalk no longer engages mechanically; instead, it returns to its initial position even when the wipers are switched on. It is switched off by moving the lever in the opposite direction.

Horn Function

The SCCM control unit records the position of the horn button. This information is transmitted by the SCCM control unit to the UEC control unit via the LS CAN.

Immobilizer Function (Immobilizer 3)

An immobilizer function (immobilizer 3) is incorporated into the SCCM control unit. The SCCM control unit communicates with the transponder in the ignition key with the aid of the transponder aerial connected to it. It evaluates the transponder signal. Even if the ignition key is recognized as valid, the identifiers of the REC, UEC, instrument panel cluster (IPC) control units are still checked. If at least 2 are recognized as valid components, the release procedure continues and communication is carried out with the ECM control unit with ignition ON. The ECM control unit requests a start release from the SCCM control unit. If release fails, the ignition key must be removed from the ignition lock so that the Key IN status can be detected again and a new release procedure started by the transponder. The conversion from analogue to digital signals is carried out by the SCCM control unit.

Loudspeaker Function

At the request of the UEC, REC, PAS, PEPS, IPC, DIS, SDM, SLM or TPMS control units, the SCCM triggers an acoustic signal from the integral loudspeaker. This signal is specific for each function. For example, the REC control unit may send a message to the SCCM indicating the frequency at which the turn signal tone should be output (normal flash frequency or faster flash frequency if turn signal is faulty). Other functions involving the sending of a sound output request to the SCCM control unit include parking light activated, door, boot or tailgate open, Park Assist, adaptive cruise control, windscreen wiper switch off and deactivate transport mode.

Steering Wheel Controls Function (Optional Equipment)

The SCCM control unit records which button on the steering wheel controls has been actuated - if several buttons have been pressed at the same time, the button with the greatest priority is always evaluated. This information is transmitted by the SCCM control unit to the DIS control unit via the CAN. Some of this information is then forwarded to the radio control unit via the DIS interface.

Info Display Function (Optional Equipment)

The SCCM control unit records that the Info Display operating switch has been actuated. This information is transmitted by the SCCM control unit to the DIS control unit via the CAN.

Steering Wheel Position Function

The SCCM module has a steering angle sensor. This sensor records the current steering angle or the current steering movement and transmits this information to the SCCM control unit. The steering angle sensor signal is used internally by the SCCM control unit to reset the turn signal. The SCCM control unit transmits the steering angle information to the ABS/ESP control unit via the HS CAN if the vehicle has ESP (optional). The EHPS also uses this information. For the ESP version, the sensor is "multi-turn" capable, i.e. it can indicate the exact angular position across the entire steering range. Vehicles without ESP are fitted with a simplified version which, after 360° starts again at 0.

Air Bag Firing Signal

The air bag firing circuit is connected through to the driver's air bag (to the ignition pellet) in the steering wheel via the contact unit of the SCCM control unit.

Key Remote Control Function

The SCCM control unit has a receiver which converts the key remote control signal. The SCCM control unit evaluates this information and transmits it to the REC via the CAN.

Main/dipped Beam Function

The SCCM control unit records the 2 positions of the main/dipped beam switch. This information is transmitted by the SCCM to the UEC control unit via the CAN.

Key Locking Function

The key locking function is only active on vehicles with automatic transmission. The TCM control unit transmits the current selector lever position to the SCCM control unit via the HS CAN. If the current selector lever position is P, the SCCM deactivates the key lock and the ignition key can be removed.

Starter Control Function

If the SCCM detects the "engine start" ignition key position, it sends a CAN message to the ECM to actuate the starter. After receiving this message, the ECM sends another bus message to the UEC via the SCCM interface. The UEC then actuates the starter relay incorporated in it. Direct actuation of the start relay by the SCCM without the "diversion" via the ECM would not be sensible as the ECM decides whether the starter should be actuated (if the engine is already running, the ECM will not send a bus message to the UEC to actuate the starter, even if the driver has turned the key to the "Start" position).

Active/Select One-Touch Buttons Function

The SCCM records the actuation of the Active/Select one-touch buttons in the steering wheel and transmits the gearshift request to the TCM / MTA via the HS CAN.

Under hood Electrical Center (UEC)

The UEC is a central module in the engine compartment near to the battery. It contains a fuse and relay box as well as a control unit. The control unit communicates with other bus users via the LS CAN bus. The UEC controls, amongst other things, the front lighting, the windscreen wipers and the horn. Various sensors are read (e.g. brake fluid level sensor) and their values are output by the UEC as bus messages.

Wiper Function

The UEC is the center of all actuated components

1. Front wiper relay
2. 4 wiper stages (one-touch wipe, intermittent, slow wipe, fast wipe). If the drivers door is opened when the fast stage is selected, the wiper is automatically reset to the slow stage. This function is programmable.
3. Rain/light sensor.
4. Intermittent function (with rain sensor fitted).
5. Wiper service position: After the ignition has been switched off and the key is in position "0", the wipers can be moved to a service position (for example to change the wipers) by actuating the wiper switch in the SCCM.
6. Rear wiper.
7. Windscreen wash system.
8. Rear window wash system (If the washer fluid level is too low, the rear window wash system will be deactivated).
9. Headlamp wash system (If the washer fluid level is too low, the headlamp wash system will be deactivated).

Exterior Lighting Function

The following functions are actuated depending on the corresponding signal input

1. Turn signal function.
2. Parking light left/right.
3. Position light.
4. Dipped beam.
5. Daytime running lamps (programmable according to country).
6. Automatic light function (if fitted with rain/light sensor).
7. Lights-on warning (if position or dipped beam lights are on and the drivers door is opened with the key removed from the ignition, a warning buzzer will sound).
8. Emergency lighting (if, when the ignition is on, the UEC does not receive any bus messages or the bus messages are illegible, the dipped beam and position light are activated).
9. "Follow me home" functions (if the headlamp flash stalk is operated with the key removed from the ignition, the lights switched off and the driver's door open, the UEC will switch on the dipped beam, the reversing lights and the tail lights for 30 seconds).
10. Main beam: The UEC will only switch on main beam if the dipped beam is switched on. (On vehicles with rain/light sensors, the main beam can only be switched on if the sensor has reported that it is "night", the dipped beam is switched on and the engine is running).
11. There are two programmable options for main beam operation: A: The UEC switches off dipped beam when main beam is operated. B: Both main beam and dipped beam are on together.
12. Headlamp flash (warning: if the key is removed and the door open, the same stalk will switch on the "follow me home" function).
13. Front fog lamps (can only be activated if the ignition is switched on and the position light or main beam are switched on).
14. Bulb check.

Data Link Connector (DLC)

The data link connector (DLC) is a standardized 16-cavity connector. Connector design and location is dictated by an industry wide standard, and is required to provide the following

1. Pin 1 GMLAN low speed communications terminal
2. Pin 4 Scan tool power ground terminal
3. Pin 5 Common signal ground terminal
4. Pin 6 High speed GMLAN serial data bus (+) terminal
5. Pin 7 Keyword 2000 serial data bus terminal
6. Pin 14 High speed GMLAN serial data bus (-) terminal
7. Pin 16 Scan tool power, battery positive voltage terminal

Serial Data Reference

The scan tool communicates over the various busses on the vehicle. When a scan tool is installed on a vehicle, the scan tool will try to communicate with every module that could be optioned into the vehicle. If an option is not installed on the vehicle, or a module is not communicating that is installed, the scan tool will not display that control module.