The automatic transmission output shaft speed sensor (AT OSS) provides vehicle speed information to the PCM. The AT OSS is a permanent magnet generator mounted to the transmission case. The AT OSS produces an AC voltage as the transmission speed sensor rotor teeth pass through the sensor's magnetic field. The AC voltage level increases as the speed of the vehicle increases. The PCM converts the AC voltage into a digital signal. The PCM uses the vehicle speed signal to determine shift timing, torque converter clutch (TCC) apply, TCC release, and gear ratio calculations.
When the PCM detects a loss of vehicle speed while the vehicle is in motion, then DTC P0503 sets. DTC P0503 is a type B DTC.
• | No TFP manual valve position switch DTC P1810. |
• | The engine is running. |
• | The time since the gear select lever change is greater than 6 seconds. |
• | An increase in output speed of 250 RPM or greater has not occurred for greater than 5 seconds. |
Output speed drops greater than 1,200 RPM for 3 seconds.
• | The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met. |
• | The PCM commands maximum line pressure. |
• | The PCM freezes transmission adapt functions. |
• | The PCM calculates output speed from input speed, engine speed, and commanded gear. |
• | The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records. |
• | The PCM stores DTC P0503 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met. |
• | The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes. |
• | A scan tool can clear the MIL/DTC. |
• | The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring. |
• | The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM. |
The numbers below refer to the step numbers on the diagnostic table.
This step tests the ability of the AT OSS to produce an AC voltage. This step also verifies the integrity of the wiring to the PCM.
This step tests the AT OSS circuit for correct resistance.
Step | Action | Value(s) | Yes | No | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic System Check - Engine Controls in Engine Controls - 2.2L (L61) or Diagnostic System Check - Engine Controls in Engine Controls - 2.2L (LN2) | ||||||||||
2 |
Important: Before clearing the DTC, use the scan tool to record the Freeze Frame and Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from the PCM. 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 Intermittent Conditions in Engine Controls - 2.2L (L61) or Intermittent Conditions in Engine Controls - 2.2L (LN2) | 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 (CKT 400) and the low signal circuit (CKT 401) of the AT OSS for being shorted together. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | -- | ||||||||||
8 | Test the high signal circuit (CKT 400) of the AT OSS for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. 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 (CKT 400) of the AT OSS for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | -- | ||||||||||
11 |
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct a condition? | -- | Go to Step 15 | Go to Step 13 | ||||||||||
12 |
Refer to Vehicle Speed Sensor Replacement .
Refer to Transmission Overhaul in Transmission Unit Repair Manual. Did you complete the repair? | -- | Go to Step 15 | -- | ||||||||||
13 | Replace the AT OSS. Refer to Vehicle Speed Sensor Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- | ||||||||||
14 | Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 2.2L (L61) or Powertrain Control Module Replacement in Engine Controls - 2.2L (LN2). 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? | -- | System OK | Go to Step 1 |
The automatic transmission output shaft speed sensor (AT OSS) provides vehicle speed information to the PCM. The AT OSS is a permanent magnet generator mounted to the transmission case. The AT OSS produces an AC voltage as the transmission speed sensor rotor teeth pass through the sensor's magnetic field. The AC voltage level increases as the speed of the vehicle increases. The PCM converts the AC voltage into a digital signal. The PCM uses the vehicle speed signal to determine shift timing, torque converter clutch (TCC) apply, TCC release, and gear ratio calculations.
When the PCM detects a loss of vehicle speed while the vehicle is in motion, then DTC P0503 sets. DTC P0503 is a type B DTC.
• | No TFP manual valve position switch DTC P1810. |
• | The engine is running. |
• | The time since the gear select lever change is greater than 6 seconds. |
• | An increase in output speed of 250 RPM or greater has not occurred for greater than 5 seconds. |
Output speed drops greater than 1,200 RPM for 3 seconds.
• | The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met. |
• | The PCM commands maximum line pressure. |
• | The PCM freezes transmission adapt functions. |
• | The PCM calculates output speed from input speed, engine speed, and commanded gear. |
• | The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records. |
• | The PCM stores DTC P0503 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met. |
• | The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes. |
• | A scan tool can clear the MIL/DTC. |
• | The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring. |
• | The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM. |
The numbers below refer to the step numbers on the diagnostic table.
This step tests the ability of the AT OSS to produce an AC voltage. This step also verifies the integrity of the wiring to the PCM.
This step tests the AT OSS circuit for correct resistance.
Step | Action | Value(s) | Yes | No | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic System Check - Engine Controls in Engine Controls - 2.4L | ||||||||||
2 |
Important: Before clearing the DTC, use the scan tool to record the Freeze Frame and Failure Records. Using the Clear Info function erases the Freeze Frame and Failure Records from the PCM. 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 Intermittent Conditions in Engine Controls - 2.4L | 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 (CKT 400) and the low signal circuit (CKT 401) of the AT OSS for being shorted together. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | -- | ||||||||||
8 | Test the high signal circuit (CKT 400) of the AT OSS for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. 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 (CKT 400) of the AT OSS for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | -- | ||||||||||
11 |
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct a condition? | -- | Go to Step 15 | Go to Step 13 | ||||||||||
12 |
Refer to Vehicle Speed Sensor Replacement .
Refer to Transmission Overhaul in Transmission Unit Repair Manual. Did you complete the repair? | -- | Go to Step 15 | -- | ||||||||||
13 | Replace the AT OSS. Refer to Vehicle Speed Sensor Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- | ||||||||||
14 | Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 2.4L. 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? | -- | System OK | Go to Step 1 |