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Hello guys,
I am trying to figure out the problem with the friend's Buick Lucerne with the 3.8L engine. The car may start OK but after 10-15 min of driving the "reduced power" message appears and the car almost stalls. The codes are U0073 (lost communication with TCM) and U0107 (lost communication with the throttle actuator). I checked the wiring, tried to monitor the CAN bus on the scope, tested ground, 12V and 5V lines on ECM, etc. It seems that the problem is intermittent and sometimes it is impossible to replicate. However, it could be somehow related to the engine heat since it sometimes appears after the engine is already hot. It is impossible to get rid of these codes. However, I managed to clear these codes a couple of times when the engine has cooled down. What else could I check?
Thanks,
Anton.
What year is the Buick?
You said you cannot clear the codes. Does that mean they come back immediately or that they continue to return after drive cycles?
I remember on certain Lucerne and Impala vehicles, on the driver's side strut tower under the hood, a grey connector that was prone to water intrusion leading to throttle actuator problems. There may even be a TSB about the problem
The car is 2008.
When the problem appears, the codes come back immediately.
I think I checked all the connections, including that connector near the strut tower. I suspect the throttle body. As I understood, it connected to the ECM through serial data - two wires, pins 7 and 16 of the throttle body connector.
