The automatic transmission output speed sensor (OSS) provides vehicle speed information to the transmission control module (TCM). The OSS is a permanent magnet generator mounted to the transmission case. The OSS produces an AC voltage as the transmission speed sensor rotor teeth pass through the magnetic field of the sensor. The AC voltage level increases as the speed of the vehicle increases. The TCM converts the AC voltage into a digital signal. The TCM uses the vehicle speed signal to determine shift timing, torque converter clutch (TCC) apply, TCC release, and gear ratio calculations.
When the TCM detects a low output speed and the vehicle has a large engine speed in a drive gear, DTC P0722 sets. DTC P0722 is a type B DTC.
This diagnostic procedure supports the following DTC:
DTC P0722 Output Speed Sensor Circuit Low Voltage
• | No MAP DTCs P0107 or P0108. |
• | No TP DTCs P0120 or P0220. |
• | No ISS DTCs P0716 or P0717. |
• | No VSS DTC P0723. |
• | The transmission range is not PARK or NEUTRAL. |
• | The TP angle is greater than 8 percent. |
• | The input speed is between 1,500-5,000 RPM. |
• | The engine torque is greater than 50 N·m (37 lb ft). |
• | The transmission fluid temperature (TFT) is greater than -40°C (-40°F). |
• | The TCC slip speed is greater than -20 RPM. |
The transmission OSS is 61 RPM or less for 4.5 seconds.
• | The TCM requests the engine control module (ECM) to illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met. |
• | The TCM commands maximum line pressure. |
• | The TCM freezes transmission adaptive functions. |
• | The TCM calculates output speed from input speed, engine speed, and commanded gear. |
• | 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 P0722 in TCM history during the second consecutive trip in which the Conditions for Setting the DTC are met. |
• | 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. |
The numbers below refer to the step numbers on the diagnostic table.
This step tests the ability of the OSS to produce an AC voltage. This step also verifies the integrity of the wiring to the TCM.
This step tests the OSS circuit for correct resistance.
Step | Action | Value(s) | Yes | No | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |||||||||||
2 |
Important: Before clearing the DTC, use the scan tool in order to record the Freeze Frame and Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from both the ECM and the TCM. Notice: Support the lower control arms in the normal horizontal position in order to avoid damage to the drive axles. Do not operate the vehicle in gear with the wheels hanging down at full travel. With the drive wheels rotating, does Transmission OSS increase when the wheel speed increases? | -- | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 | ||||||||||
Can a voltage greater than the specified value be obtained? | 0.5 V AC | Go to Step 14 | Go to Step 4 | |||||||||||
Is the circuit resistance within the specified range? | 1,530-1,870 ohms | Go to Step 8 | Go to Step 5 | |||||||||||
5 | Is the circuit resistance greater than the specified value? | 1,870 ohms | Go to Step 11 | Go to Step 6 | ||||||||||
6 |
Is the circuit resistance less than the specified value? | 1,530 ohms | Go to Step 7 | Go to Step 13 | ||||||||||
7 | Test the high signal circuit and the low signal circuit of the OSS for being shorted together. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 15 | -- | ||||||||||
8 | Test the high signal circuit of the OSS for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 9 | ||||||||||
9 |
Does the DMM display system voltage? | -- | Go to Step 10 | Go to Step 12 | ||||||||||
10 | Test the high signal circuit of the OSS for a short to voltage. Refer to Testing for a Short to Voltage and Wiring Repairs . Did you find and correct the condition? | -- | Go to Step 15 | -- | ||||||||||
11 |
Did you find and correct a condition? | -- | Go to Step 15 | Go to Step 13 | ||||||||||
12 |
Did you complete the repair? | -- | Go to Step 15 | -- | ||||||||||
13 | Replace the OSS. Refer to Vehicle Speed Sensor Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- | ||||||||||
14 | Replace the TCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 15 | -- | ||||||||||
15 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | Go to Step 16 | Go to Step 2 | ||||||||||
16 | With the scan tool, observe the stored information, capture info and DTC info. Does the scan tool display any DTCs that you have not diagnosed? | -- | System OK |