With 4L80E Automatic Transmission

System Voltage Diagnostic Chart:

System Voltage Circuit:

CIRCUIT DESCRIPTION:
DTC 53 will set when the ignition is "ON" and PCM terminal "D1" or TCM terminal "A12" voltage is greater than 19.5 volts for 2 seconds.
During the time the fault is present, the pressure control solenoid is turned "OFF," transmission shifts immediately to 2nd gear, and TCC operation is inhibited. The setting of additional codes may result.

TEST DESCRIPTION:
Number(s) below refer to circled number(s) on the diagnostic chart.

1. Normal battery voltage is between 9-15 volts.

2. This test checks if the high voltage reading is due to the generator, CKT 440 or PCM/TCM, with engine operating, check voltage at the battery. If the voltage is greater than 15 volts, the PCM/TCM is OK.

3. This test checks to see if generator is faulty under load condition. If the voltage is greater than 15 volts, refer to appropriate section.

NOTE ON INTERMITTENTS:
Charging battery with a battery charger and jump-starting engine may set DTC 53. If a DTC sets, when an accessory is operated, check for poor connections or excessive current draw. RefeRto SECTION 6D3 for circuit details. Also, check for poor connections at starter solenoid or fusible link.