DTC B334: Loss Of ECM Data: Description

Code B334 will set if the ignition is on and the BCM is not able to exchange data with the ECM (if any other communication codes are stored along with B334, see 1989 SELF-DIAGNOSTICS -- ALLANTE article in ENGINE PERFORMANCE. When this is the only communication code stored, the problem must be one of the following, an open circuits 800E and 800F or 800E and 800D, an open or short to ground in circuit 439 or 1605, or a faulty ECM or ECM Calpack.

During the time the failure is present, a failsoft value equal to 100°C will be used for the coolant temperature, the cooling fans will be commanded to high speed, and no ECM diagnostic information will be available for display. Also, while in the service diagnostic mode, this code will remain active, always checking for proper operation.