The Transmission Control Module Scan Tool Data List contains all transmission related parameters that are available on the scan tool. The list is arranged in alphabetical order. A given parameter may appear in any one of the data lists, and in some cases may appear more than once, or in more than one data list in order to group certain related parameters together.
The values below represent a typical display recorded from a properly functioning system.
Note: Do not use a scan tool that displays faulty data. Report the condition to the scan tool manufacturer. The use of a faulty scan tool can result in misdiagnosis and the unnecessary replacement of components.
Only the parameters listed below are used/referenced in this manual for diagnosis. If a scan tool displays other parameters, those values are not recommended by General Motors for use in diagnosis.
If all values are within the expected range described below, refer to Symptoms - Automatic Transmission for diagnosis.
The scan tool values from a properly functioning transmission may be used for comparison with the transmission you are diagnosing. The values below represent a typical display recorded from a properly functioning system.
Parameter | System State | Expected Value | Description |
|---|---|---|---|
Operating Conditions: Engine at idle, upper radiator hose hot, closed throttle, transmission in Park, closed loop operation, accessories OFF, brake pedal not applied. | |||
1–2 Shift Time | Varies | Seconds | This parameter displays the actual time of the last adaptable 1-2 shift. The shift time is based on the gear ratio change after the commanded 1-2 shift. |
2–3 Shift Time | Varies | Seconds | This parameter displays the actual time of the last adaptable 2-3 shift. The shift time is based on the gear ratio change after the commanded 2-3 shift. |
3–4 Shift Time | Varies | Seconds | This parameter displays the actual time of the last adaptable 3-4 shift. The shift time is based on the gear ratio change after the commanded 3-4 shift. |
4–5 Shift Time | Varies | Seconds | This parameter displays the actual time of the last adaptable 4-5 shift. The actual shift time is obtained by measuring the time required for the input shaft to decelerate from the previous ratio to the current ratio. |
5–6 Shift Time | Varies | Seconds | This parameter displays the actual time of the last 5-6 shift. The shift time is base on the gear ratio change after the commanded 5-6 shift. |
Brake Pedal Switch | Released | Applied/Released | This parameter displays the status of the brake switch circuit input. Applied indicates a zero voltage input, brake pedal applied. Released indicates a voltage input, brake pedal released. The scan tool displays Applied or Released. |
Calculated Throttle Position | Varies | % | This parameter displays a calculated value, which is determined by the accelerator pedal position and the actual throttle position, used to optimize transmission controls. It represents the driver’s intended request for torque or acceleration. The range is 0-100%, where 0% represents an idle or coast request and 100% represents a request for wide open throttle (WOT). |
Control Module Voltage Signal | 9-19 | Volts | This parameter displays the system voltage measured at the module wake up signal feed. |
Driver Shift Control Mode | Inactive | Active/Inactive | This parameter displays Active or Inactive. The scan tool displays Active when the gear selector is in the manual mode (M) position or left of the D position, which enables TAP shift. The scan tool displays Inactive when the gear selector is not in the M or left of D position, TAP shift disabled. |
Driver Shift Request | None | Upshift / Downshift / None / Invalid | This parameter displays the current request from the TAP Shift System. This parameter will display up shift, downshift or invalid depending on the amount of voltage measured at the remote shift selector input and also will display none when there is no request. |
Engine Coolant Temperature | Varies | °C (°F) | This parameter displays the input signal from the engine coolant temperature (ECT) sensor. ECT is high at 151°C (304°F) when the signal voltage is low (0 V). ECT is low at −40°C (−40°F) when the signal voltage is high (5 V). This parameter value is determined by the engine control module and communicated to the TCM through the High Speed GMLAN Serial Data link. |
Engine Speed | Varies | RPM | This parameter displays the rotational speed of the engine expressed as revolutions per minute. This parameter value is determined by the engine control module and communicated to the TCM through the High Speed GMLAN Serial Data link. |
Engine Torque | Varies | N·m (lb ft) | This parameter displays a calculated value based on engine load, throttle position, mass air flow, and other engine inputs. This parameter is accurate to within 20 N·m (15 lb ft) of actual measured engine torque. This parameter value is determined by the engine control module and communicated to the TCM through the High Speed GMLAN Serial Data link. |
Gear Command | 1 | 1, 2, 3, 4, 5, or 6 | This parameter displays the current commanded state of the shift solenoid valves. The scan tool displays 1, 2, 3, 4, 5, or 6. |
Gear Ratio | Varies | Ratio | This parameter displays the actual transmission gear ratio. The scan tool displays the gear ratio calculated from the automatic transmission (AT) input speed sensor (ISS) and the automatic transmission (AT) output speed sensor (OSS) inputs. |
High Side Driver 1 | On | On/Off | This parameter displays the state of the High Side Driver 1. The scan tool displays On or Off. |
High Side Driver 1 Circuit Low Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a short to ground exists in the high side driver 1 circuit. The scan tool displays OK, Malfunction, or Not Run. |
High Side Driver 1 Circuit High Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a short to voltage exists in the high side driver 1 circuit. The scan tool displays OK, Malfunction, or Not Run. |
High Side Driver 1 Circuit Open Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether an open exists in the high side driver 1 circuit. The scan tool displays OK, Malfunction, or Not Run. |
Ignition Voltage | 9–19 | Volts | This parameter displays the system voltage measured at the ignition feed. |
Internal Mode Switch | Park | Park–Drive 1, Open, Invalid | This parameter displays PARK, PARK/REVERSE, REVERSE, REVERSE/NEUTRAL, NEUTRAL, NEUTRAL/DRIVE 4, DRIVE 4, DRIVE 4/DRIVE 3, DRIVE 3, DRIVE 3/DRIVE 2, DRIVE 2, DRIVE 2/DRIVE 1, DRIVE 1 or INVALID. The IMS Range display represents a decoded status of the four inputs from the IMS. The combination of IMS inputs are used to determine what position the manual valve is in at any time. |
Internal Mode Switch A/B/C/P | Varies | High/Low | This parameter displays the status of the four A/B/C/P inputs from the automatic transmission internal mode switch. HI indicates an ignition voltage signal and LOW indicates a 0 voltage signal. The scan tool will display High/Low, High/Low, High/Low, High/Low. |
ISS/OSS Supply Voltage | OK | OK, Out of Range | This parameter displays OK, Out of Range. |
Last Shift Time | Varies | Seconds | This parameter displays the actual time of the last up shift. This value is only accurate if the shift was adaptable. |
Line Pressure Control Solenoid Valve Control Circuit Low Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a short to ground exists in the line pressure control valve 2 control circuit. The scan tool displays OK, Malfunction, or Not Run. |
Line Pressure Control Solenoid Valve Control Circuit High Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a short to ground exists in the line pressure control valve 2 control circuit. The scan tool displays OK, Malfunction, or Not Run. |
Line Pressure Control Solenoid Valve Performance Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a performance issue exists in the line pressure control solenoid valve control circuit by comparing the commanded current with the expected current. The scan tool displays OK, Malfunction, or Not Run. |
Line Pressure Control Solenoid Valve Pressure Command | Varies | kPa (psi) | This parameter displays results in kPa (psi). |
Pressure Control Solenoid Valve 2 Control Circuit Low Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a short to ground exists in the pressure control solenoid valve 2 control circuit. The scan tool displays OK, Malfunction, or Not Run. |
Pressure Control Solenoid Valve 2 Control Circuit High Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a short to voltage exists in the pressure control solenoid valve 2 control circuit. The scan tool displays OK, Malfunction, or Not Run. |
Pressure Control Solenoid Valve 2 Performance Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a performance issue exists in the pressure control solenoid valve 2 control circuit by comparing the commanded current with the expected current. The scan tool displays OK, Malfunction, or Not Run. |
Pressure Control Solenoid Valve 2 Pressure Command | Varies | kPa (psi) | This parameter displays kPa (psi). |
Pressure Control Solenoid Valve 3 Control Circuit Low Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a short to ground exists in the pressure control solenoid valve 3 control circuit. The scan tool displays OK, Malfunction, or Not Run. |
Pressure Control Solenoid Valve 3 Control Circuit High Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a short to voltage exists in the pressure control solenoid valve 3 control circuit. The scan tool displays OK, Malfunction, or Not Run. |
Pressure Control Solenoid Valve 3 Performance Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a performance issue exists in the pressure control solenoid valve 3 control circuit by comparing the commanded current with the expected current. The scan tool displays OK, Malfunction, or Not Run. |
Pressure Control Solenoid Valve 3 Pressure Command | Varies | kPa (psi) | This parameter displays kPa (psi). |
Pressure Control Solenoid Valve 4 Control Circuit Low Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a short to ground exists in the pressure control solenoid valve 4 control circuit. The scan tool displays OK, Malfunction, or Not Run. |
Pressure Control Solenoid Valve 4 Control Circuit High Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a short to voltage exists in the pressure control solenoid valve 4 control circuit. The scan tool displays OK, Malfunction, or Not Run. |
Pressure Control Solenoid Valve 4 Performance Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a performance issue exists in the pressure control solenoid valve 4 control circuit by comparing the commanded current with the expected current. The scan tool displays OK, Malfunction, or Not Run. |
Pressure Control Solenoid Valve 4 Pressure Command | Varies | kPa (psi) | This parameter displays kPa (psi). |
Pressure Control Solenoid Valve 5 Control Circuit Low Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a short to ground exists in the pressure control solenoid valve 5 control circuit. The scan tool displays OK, Malfunction, or Not Run. |
Pressure Control Solenoid Valve 5 Control Circuit High Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a short to voltage exists in the pressure control solenoid valve 5 control circuit. The scan tool displays OK, Malfunction, or Not Run. |
Pressure Control Solenoid Valve 5 Performance Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a performance issue exists in the pressure control solenoid valve 5 control circuit by comparing the commanded current with the expected current. The scan tool displays OK, Malfunction, or Not Run. |
Pressure Control Solenoid Valve 5 Pressure Command | Varies | kPa (psi) | This parameter displays kPa (psi). |
Replicated OSS CKT Status | OK | OK, Open/Short to GND, Short to Volts, Indeterminate | This parameter displays OK, Open/Short to GND, Short to Volts, Indeterminate. |
Shift Solenoid Valve 1 | On | On/Off | This parameter displays the commanded state of the reverse, 1st shift solenoid valve (S1). The scan tool displays On/Off. |
Shift Solenoid Valve 1 Control Circuit Low Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a short to ground exists in the shift solenoid valve 1 control circuit. The scan tool displays OK, Malfunction, or Not Run. |
1-2 Shift Solenoid Valve Control Circuit High Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a short to voltage exists in the shift solenoid valve 1 control circuit. The scan tool displays OK, Malfunction, or Not Run. |
Shift Solenoid Valve 1 Control Circuit Open Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether an open exists in the shift solenoid valve 1 control circuit. The scan tool displays OK, Malfunction, or Not Run. |
Steady State TAP 1st Gear | Varies | kPa (psi) | This parameter displays the amount of transmission adaptive pressure (TAP), which modifies the commanded clutch apply pressures. |
Steady State TAP 1st Gear TCC Applied | Varies | kPa (psi) | This parameter displays the amount of transmission adaptive pressure (TAP), which modifies the commanded clutch apply pressures. |
Steady State TAP 2nd Gear | Varies | kPa (psi) | This parameter displays the amount of transmission adaptive pressure (TAP), which modifies the commanded clutch apply pressures. |
Steady State TAP 2nd Gear TCC Applied | Varies | kPa (psi) | This parameter displays the amount of transmission adaptive pressure (TAP), which modifies the commanded clutch apply pressures. |
Steady State TAP 3rd Gear | Varies | kPa (psi) | This parameter displays the amount of transmission adaptive pressure (TAP), which modifies the commanded clutch apply pressures. |
Steady State TAP 3rd Gear TCC Applied | Varies | kPa (psi) | This parameter displays the amount of transmission adaptive pressure (TAP), which modifies the commanded clutch apply pressures. |
Steady State TAP 4th Gear | Varies | kPa (psi) | This parameter displays the amount of transmission adaptive pressure (TAP), which modifies the commanded clutch apply pressures. |
Steady State TAP 4th Gear TCC Applied | Varies | kPa (psi) | This parameter displays the amount of transmission adaptive pressure (TAP), which modifies the commanded clutch apply pressures. |
Steady State TAP 5th Gear | Varies | kPa (psi) | This parameter displays the amount of transmission adaptive pressure (TAP), which modifies the commanded clutch apply pressures. |
Steady State TAP 5th Gear TCC Applied | Varies | kPa (psi) | This parameter displays the amount of transmission adaptive pressure (TAP), which modifies the commanded clutch apply pressures. |
Steady State TAP 6th Gear | Varies | kPa (psi) | This parameter displays the amount of transmission adaptive pressure (TAP), which modifies the commanded clutch apply pressures. |
Steady State TAP 6th Gear TCC Applied | Varies | kPa (psi) | This parameter displays the amount of transmission adaptive pressure (TAP), which modifies the commanded clutch apply pressures. |
Steady State TAP Reverse | Varies | kPa (psi) | This parameter displays the amount of transmission adaptive pressure (TAP), which modifies the commanded clutch apply pressures. |
TCC Pressure Control Solenoid Valve Control Circuit Low Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a short to ground exists in the TCC pressure control solenoid valve control circuit. The scan tool displays OK, Malfunction, or Not Run. |
TCC Pressure Control Solenoid Valve Control Circuit High Voltage Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a short to voltage exists in the TCC pressure control solenoid valve control circuit. The scan tool displays OK, Malfunction, or Not Run. |
TCC Pressure Control Solenoid Valve Performance Test Status | OK | OK, Malfunction, Not Run | This parameter displays whether a performance issue exist in the TCC pressure control solenoid valve control circuit by comparing the commanded current with the expected current. The scan tool displays OK, Malfunction, or Not Run. |
TCC Pressure Control Solenoid Valve Pressure Command | Varies | kPa (psi) | This parameter displays results in kPa (psi). |
TCC Slip Speed | Varies | RPM | This parameter displays the difference between transmission input speed and engine speed. A negative value indicates that the engine speed is less than the input speed, deceleration. A positive value indicates that the engine speed is greater than the input speed, acceleration. A value of zero indicates that the engine speed is equal to the input speed, TCC applied. |
TCM Power-Up Temperature | Varies | °C (°F) | This displays the value of the temperature sensor inside the control solenoid and valve assembly. |
TCM Temperature | Varies | °C (°F) | This displays the temperature of the TCM. This parameter displays results in °C (°F). |
Transmission Fluid Life | Varies | % | This parameter displays the transmission oil life remaining. The scan tool displays the remaining oil life as a percentage. The transmission oil life is calculated based on fluid temperature and engine run time. |
Transmission Fluid Temperature | Varies | °C (°F) | This parameter displays the input signal of the transmission fluid temperature sensor. Transmission fluid temperature is high 151°C (304°F) when signal voltage is low, 0 V, and transmission fluid temperature is low −40°C (−40°F ) when signal voltage is high, 5 V. |
Transmission Hot Mode | On/Off | On/Off | When The transmission fluid temperature is above a temperature which varies by calibration, the TCM will alter the shift pattern until the temperature drops below a value which varies by calibration. |
Transmission ISS | Varies | RPM | This parameter displays the rotational speed of the transmission input shaft. The scan tool displays input shaft speed is revolutions per minute (RPM). |
Transmission OSS | Varies | RPM | This parameter displays the rotational speed of the transmission output shaft expressed as revolutions per minute. |
Output Control | Description |
|---|---|
TCC Pressure Control Solenoid Valve - Dynamic Test |
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TCC Pressure Control Solenoid Valve - Static Test |
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Shift Solenoid:
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Line Pressure Control Solenoid Valve |
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Clutch PC Solenoids:
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Shift Transmission Gear |
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Transmission Adaptive Values Learn | The TCM commands pressure to the clutches to learn the transmission adaptive values. As the procedure is being performed, the scan tool provides operator instructions. Test may not start or may abort for the following conditions:
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