Driver Fault

These faults indicate a problem with a control solenoid or wiring in your transmission.

  • Your COMPUSHIFT II can detect an open circuit or short circuit on the solenoid circuits. It signals any of these conditions by displaying the appropriate fault for the solenoid circuit, called a “driver”.

COMPUSHIFT II may also temporarily disconnect that solenoid from the circuit.

Different transmissions uses different numbers of solenoid drivers for different functions. You can refer to the Connector Pinouts charts for an exact explanation of which driver runs which solenoid.


TPS Signal Low

This fault indicates a TPS signal less than that allowed by the current calibration. This can indicate faulty wiring, incorrect calibration, or a faulty TPS. In some cases, this can also be caused by cable slippage or an incorrect initial calibration.

  • Repeat the calibration procedure before attempting other diagnostics.

TPS Signal High

This fault indicates a TPS signal greater than that allowed by the current calibration. This can indicate faulty wiring, incorrect calibration, or a faulty TPS. In some cases, this can also be caused by an incorrect initial calibration.

  • Repeat the calibration procedure before attempting other diagnostics.

Both TPS Signal Low & TPS Signal High

If both the “TPS Signal High” and “TPS Signal Low” codes are indicated immediately after power is applied to COMPUSHIFT II, this indicates a lack of valid TPS calibration.

  • You must calibrate the TPS by following the instructions in Checkout and Testing.
  • The TPS sensor must move through at least a quarter of its full stroke to calibrate properly.

 

COMPUSHIFT II generally comes from the factory without TPS calibration, so these codes will appear as factory defaults prior to the first calibration. Also, if you reset COMPUSHIFT II using the optional Display, these codes will revert to factory defaults. (As a failsafe, when TPS is not calibrated, COMPUSHIFT II uses a constant value of 50% throttle.)


Transmission Temp Sensor

Indicates COMPUSHIFT II has received a temperature signal from the transmission that’s out of the sensor’s possible operating range, and it usually means the sensor has failed, or the wiring is faulty.

In order to preserve shift quality, COMPUSHIFT II must have an accurate measurement of your transmission’s temperature.


Transmission Over Temp

Indicates your transmission is running too hot.

Turn off your vehicle as soon as possible as transmission damage is imminent. This fault is triggered when transmission temperature exceeds 275°F / 135°C for 10 seconds or more.


EEPROM Fault

Indicates the internal memory system of your COMPUSHIFT II Controller has suffered a failure.

Contact HGM Automotive Electronics for repair or replacement of your Controller.


System Voltage Low

Indicates COMPUSHIFT II detects that the 12-volt power supply has dropped too low for an extended period.

  • If you have an indication of this fault, make sure your COMPUSHIFT II has a good connection to 12-volt power and ground, and that your battery is fully charged.

System Voltage High

Indicates that COMPUSHIFT II detects that the 12-volt power supply has exceeded the normal operating range.

This condition can damage COMPUSHIFT II and other components in your vehicle. This fault usually indicates a failure of the vehicle charging system.

Do not disconnect your battery while the vehicle engine is running. Doing so could damage COMPUSHIFT II and any other vehicle electronics.


Invalid PRNDL

Indicates an invalid signal combination has been received from the transmission gear selector (PRNDL) switch.

Faulty wiring, a failed switch, or a hydraulic problem in the transmission can cause this.


System Over Temp

Indicates the internal temperature of COMPUSHIFT II has exceeded a safe range.

  • COMPUSHIFT II will automatically turn itself off 25 seconds after this fault is displayed. The status LED will go dark.

This fault can occur if a partial short exists in the transmission wiring, or if COMPUSHIFT II is overheated due to improper mounting.