P1882

P1882






Circuit Description

The transmission control module (TCM) uses the input and output shaft speed sensor input signals to calculate the speed ratio. The speed ratio is then compared to the desired speed ratio, and the difference between the two values is the speed ratio error. If the ratio control response is slow or jerky, a fail counter is incremented a number of counts depending upon the magnitude of the speed ratio error above a calibrated threshold. Conversely, if the ratio control response is smooth and the speed ratio is close to the desired speed ratio the fail counter will be decremented.

When the fail counter has accumulated a calibrated number of fail counts, DTC 1882 sets. DTC P1882 is a type A DTC.

Conditions For Running the DTC

- No HSCAN DTCs U2103, U2104, or U2105.
- No engine torque HSCAN DTC P1779.
- No transmission range switch DTCs P0705, or P1756.
- No OSS DTCs P0722, or P0723.
- No ISS DTCs P0716, or P0717.
- No ratio control motor DTCs P1883, P1884, P1885, or P1886.
- No TCC enable solenoid valve DTCs P1888, or P1889.
- The ignition voltage is 8-18 volts.
- The engine speed is greater than 500 RPM for 5 seconds.
- The selected range is DRIVE.
- The time since the gear select lever change is greater than 6 seconds.
- The transmission fluid temperature is greater than 21°C (70°F).
- The APP angle is greater than 5 percent.
- The transmission input shaft speed is greater than 700 RPM.
- The transmission output shaft speed is greater than 400 RPM.
- The speed ratio is between 0.35-1.1.
- The absolute value of the difference between the speed ratio and the desired speed ratio is greater than 0.42.

Conditions For Setting the DTC

- When the fail counter has accumulated 10,000 fail counts.

Actions Taken When the DTC Sets

- The TCM requests the ECM to illuminate the malfunction indicator lamp (MIL).
- The TCM moves the speed ratio towards a target ratio and then freezes ratio changes.
- The TCM discontinues use of the closed loop ratio control algorithm. This causes the speed ratio to be defaulted and possibly not accurate. The resulting open loop control may or may not provide optimum ratio performance.
- The TCM inhibits TCC engagement.
- The TCM commands maximum pressure to the input clutch.
- The TCM freezes garage shift transmission adaptive functions.
- The ECM records the operating conditions when the Conditions for Setting the DTC are met. The ECM stores this information as Freeze Frame and Failure Records.
- The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records.
- The TCM stores DTC P1882 in TCM history.

Conditions For Clearing the DTC

- The ECM turns OFF the MIL after the third consecutive drive trip in which the TCM does not send a MIL illumination request.
- A scan tool can clear the MIL/DTC.
- The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission related diagnostic fault occurring.
- The TCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the TCM.

Diagnostic Aids

- Inspect for intermittent automatic transmission input shaft speed sensor (AT ISS) circuit conditions.
- Inspect for an incorrect calibration.
- A misaligned variable ratio control valve lever will cause DTC P1882 to set. One end of the lever must be properly positioned in the ratio control motor pintle, and the opposite end of the lever must be properly positioned in the variable drive pulley follower, which is located on the case cover. If the transmission case cover assembly has been previously removed for service, and was installed after the valve body was installed, misalignment of the lever is possible.
- A missing or damaged primary pulley snap ring, damaged ratio control motor or a leaking secondary pulley can cause DTC P1882 to set.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

2. Proper fluid level is important to the normal operation of the transmission.
6. This determines if the transmission is working properly until the TCC system is going to be engaged. If the TCC enable solenoid is not enabled at this point, the forward clutch may slip.
9. With the ignition ON and the engine OFF, the ratio control motor will normally make a "whine" noise like an electric hand drill. If the ratio control motor is damaged, the noise will become less constant and start to sound like a "tick" noise like a clock or watch. Finally, when the ratio control motor is frozen, it will produce no noise.