P1793

Test 492 - 497:

Test 498 - 499:

Symptom:
P1793-TRD LINK COMMUNICATION ERROR

When Monitored:
Whenever the engine is running.

Set Condition:
When the TCM sends multiple TRD messages to the PCM and the TCM does not receive a response from the PCM. The code also sets when less than 3 volts are present at the relay output (switched battery) terminals at the TCM, when TCM is energizing the relay.

POSSIBLE CAUSES
CHECKING SYMPTOMS AND POSSIBLE CAUSES
LOW BATTERY VOLTAGE CAUSING SYMPTOM
TORQUE MANAGEMENT REQUEST CIRCUIT OPEN
TORQUE MANAGEMENT REQUEST CIRCUIT SHORT TO GROUND
TCR TORQUE MANAGEMENT REQUEST SIGNAL SHORTED
PCM TORQUE MANAGEMENT REQUEST SIGNAL OPEN DEFAULT
INTERMITTENT CODE P1793