During normal driving modes the PCM/TC adapts line pressure to prevent clutch slip and harsh shifts. This is accomplished by modulating the pressure control solenoid ground, 1530, to raise or lower pressure. An open circuit equals high pressure. A grounded circuit equals low pressure. When the PCM opens the circuit, the voltage is monitored to check for proper circuit conditions.
DTC P0746 is set when the PCM has detected voltage monitored at terminal J4A03, circuit 1530, is less than 2-2.5 volts when the pressure control solenoid is switched OFF electrically by the PCM, twice per ignition cycle.
Numbered steps below refer to numbered steps on the chart.
Monitor the DTC menu Code Status for Pass Since Code Clear and Pass This Ignition Cycle. When both have passed, the repair is verified.
Criteria for pass:
• | The engine is running. |
• | Power is present at the solenoids and no active faults exist for this solenoid. |
• | This DTC may set or intermittent harsh upshifts may be caused by a poor electrical connection at either the PCM, solenoid connector plate, or UHJB actuator terminals. Wiggling the connectors while performing an actuator quick test may help isolate the problem area. |
• | No 2nd, 3rd, 4th gear, DTCs P0732, P0733, or P0734 are set if the circuit is grounded, low line. The vehicle will not shift out of first. |
• | If the circuit is open that equals high line pressure. |
When the PCM detects a fault in the circuit, an open, ground, or short, the PCM will open the circuit internally to protect the circuit.