Malibu V6-3.5L VIN 8 (2004)
Steps 9-13
The numbers below refer to the step numbers on the diagnostic table.
2. A partial loss or intermittent loss of communication in the class 2 serial data circuit uses a different procedure than a total loss of communication
of the class 2 serial data circuit.
10. If there are no current DTCs that begin with the letter "U", the communication concern has been repaired.
11. The communication concern may have prevented diagnosis of the customer complaint.
Scan Tool Does Not Communicate With High Speed GMLAN Device
SCAN TOOL DOES NOT COMMUNICATE WITH HIGH SPEED GMLAN DEVICE
Modules connected to the high speed GMLAN serial data circuits monitor for serial data communications on the high speed GMLAN network during
normal vehicle operation. Operating information and commands are exchanged among the modules. When a module detects a bus-off condition a
DTC U0001 or U2100 will be set. These DTCs can be retrieved as history only.
The high speed GMLAN serial data buss uses two 120 ohms terminating resistors that are in parallel with the high speed GMLAN (+) and (-) circuits.
One of the resistors is connected at the data link connector (DLC) end of the link and the other is at the engine management module, engine control
module (ECM) or powertrain control module (PCM), end of the link. The DLC terminating resistor resides internally in the BCM. When testing for a