Powertrain Controls - ECM/PCM

DTC 75 System Voltage Low:

System Voltage:

CIRCUIT DESCRIPTION
CKT 440 is the battery feed for the Powertrain Control Module (PCM).

DTC 75 WILL SET WHEN
The ignition is "ON" and PCM terminal "E16" voltage is less than the graduated scale of: -40 °C (-40 °F) = 7.3 volts, 90 °C (194 °F) = 10.3 volts, or 150 °C (304 °F) = 11.7 volts, with engine speed greater than 1000 RPM for 4 seconds.

ACTION TAKEN (PCM WILL DEFAULT TO)
During the time the failure is present, the pressure control solenoid is turned "OFF," soft landing to default third gear and Torque Converter Clutch (TCC) operation is inhibited. (The setting of additional diagnostic trouble codes may result.) DTC 75 will be stored in the PCM memory but will not turn "ON" the MIL (Malfunction Indicator Lamp).

DTC 75 WILL CLEAR WHEN
The fault condition(s) no longer exist.

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This test checks for normal battery voltage between 9-15 volts.
2. This test checks if the low voltage display is due to the generator, CKT 440, or PCM, while the engine is running. If the voltage is less than 8.6 volts, the PCM is OK.

DIAGNOSTIC AIDS
CKT 440 supplies battery voltage to the PCM.
Charging battery with a battery charger and jump-starting engine may set DTC 53. If diagnostic trouble code sets when an accessory is operated, check for poor connections or excessive current draw. Refer to Starting and Charging. Starting and Charging
Also, check for poor connections at starter solenoid or fusible link.