DTC P0503 3.8 L
Circuit Description
The vehicle speed sensor (VSS) assembly provides vehicle speed information to the powertrain control module (PCM). The VSS assembly is a permanent magnet generator. The VSS produces an AC voltage as rotor teeth on the transmission output shaft pass through the sensor's magnetic field. The AC voltage level and the number of pulses increase as the speed of the vehicle increases. The PCM converts the voltage to vehicle speed. The PCM uses the vehicle speed signal to determine shift timing and torque converter clutch (TCC) scheduling.
When the PCM detects an unrealistically large drop in the vehicle speed, then DTC P0503 sets. DTC P0503 is a type B DTC.
Conditions for Running the DTC
| • | No TFP manual valve position switch DTC P1810. |
| • | The engine speed is greater than 450 RPM for 5 seconds. |
| • | The engine is not in fuel cutoff. |
| • | The time since the last gear range change is greater than 6 seconds. |
| • | The transmission output speed rise does not exceed 250 RPM within 2 seconds. |
Conditions for Setting the DTC
The transmission output speed drops by greater than 1300 RPM for 3 seconds when the transmission is not in PARK or NEUTRAL.
Action Taken When the DTC Sets
| • | 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 a soft landing to second gear when the engine speed is less than 2500 RPM. |
| • | The PCM commands maximum line pressure. |
| • | The PCM inhibits TCC engagement. |
| • | The PCM inhibits 4th gear if the transmission is in hot mode. |
| • | The PCM freezes shift adapts from being updated. |
| • | 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. |
Conditions for Clearing the MIL/DTC
| • | 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 fault no longer exists and/or the ignition switch is OFF long enough in order to power down the PCM. |
Diagnostic Aids
Inspect for ABS DTCs. A faulty ABS condition may contribute to setting DTC P0503.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain Diagnostic System Check? | -- | Go to Diagnostic System Check - Engine Controls in Engine Controls - 3.8 L | |
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 the PCM. Does the Scan Tool Transmission OSS drop or fluctuate more than the specified value? | 1300 RPM | Go to Intermittent Conditions in Engine Controls - 3.8 L | |
Does the resistance measure within the specified range? | 1377-3355 ohms | |||
Does the voltage measure greater than the specified value? | 0.5 volts | |||
5 | Measure the resistance from terminal C1-64 to ground. Does the resistance measure greater than the specified value? | 50 K ohms | ||
6 |
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
7 |
Does the resistance measure within the specified range? | 1377-3355 ohms | ||
8 | Was the resistance measured in Step 3 greater than the specified value? | 3355 ohms | ||
9 |
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | -- | |
10 |
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | -- | |
11 | Test the high circuit (CKT 400) and the low circuit (CKT 401) of the VSS assembly for a short together. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | -- | |
12 |
Did you find and correct the condition? | -- | ||
13 | Replace the VSS assembly. Refer to Vehicle Speed Sensor Replacement . Did you complete the replacement? | -- | -- | |
14 | Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 3.8 L. Did you complete the replacement? | -- | -- | |
15 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | System OK |
DTC P0503 5.7 L
Circuit Description
The vehicle speed sensor (VSS) assembly provides vehicle speed information to the powertrain control module (PCM). The VSS assembly is a permanent magnet generator. The VSS produces an AC voltage as rotor teeth on the transmission output shaft pass through the sensor's magnetic field. The AC voltage level and the number of pulses increase as the speed of the vehicle increases. The PCM converts the voltage to vehicle speed. The PCM uses the vehicle speed signal to determine shift timing and torque converter clutch (TCC) scheduling.
When the PCM detects an unrealistically large drop in vehicle speed, then DTC P0503 sets. DTC P0503 is a type B DTC.
Conditions for Running the DTC
| • | No TFP manual valve position switch DTC P1810. |
| • | The time since the last gear range change is greater than 6 seconds. |
| • | The engine speed is greater than 450 RPM. |
| • | The engine is not in fuel cutoff. |
| • | The transmission output speed rise does not exceed 600 RPM within 2 seconds. |
Conditions for Setting the DTC
The transmission output speed drop is greater than 1300 RPM for 3 seconds when the transmission is not in PARK or NEUTRAL.
Action Taken When the DTC Sets
| • | 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 a soft landing to second gear. |
| • | The PCM commands maximum line pressure. |
| • | The PCM inhibits TCC engagement. |
| • | The PCM inhibits 4th gear if the transmission is in hot mode. |
| • | The PCM freezes shift adapts from being updated. |
| • | 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. |
Conditions for Clearing the MIL/DTC
| • | 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 fault no longer exists and/or the ignition switch is OFF long enough in order to power down the PCM. |
Diagnostic Aids
| • | Test circuits 821 and 822 for electromagnetic interferences (EMI) induced by a wiring harness incorrectly routed too near the spark plug wires. |
| • | Inspect for ABS DTCs. A faulty ABS condition may contribute to setting DTC P0503. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
Disable the traction control system when performing this step. When the ignition switch is cycled OFF and then back ON, the traction control system defaults to ON.
-
This step tests the VSS assembly circuit.
-
This step tests the integrity of the VSS assembly.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain Diagnostic System Check? | -- | Go to Diagnostic System Check - Engine Controls in Engine Controls - 5.7 L | |
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 the PCM. Does the Scan Tool Transmission OSS drop or fluctuate more than the specified value? | 1300 RPM | Go to Intermittent Conditions in Engine Controls - 5.7 L | ||
Does the resistance measure within the specified range? | 1377-3355 ohms | |||
Does the voltage measure greater than the specified value? | 0.5 volts | |||
5 | Measure the resistance from terminal C2-21 to ground. Does the resistance measure greater than the specified value? | 50 K ohms | ||
6 |
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||
7 |
Does the resistance measure within the specified range? | 1377-3355 ohms | ||
8 | Was the resistance measured in Step 3 greater than the specified value? | 3355 ohms | ||
9 | Test the high signal circuit (CKT 821) of the VSS assembly for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | -- | |
10 |
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | -- | |
11 | Test the high signal circuit (CKT 821) and the low signal circuit (CKT 822) of the VSS assembly for a short together. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | -- | |
12 |
Did you find and correct the condition? | -- | ||
13 | Replace the VSS assembly. Refer to Vehicle Speed Sensor Replacement . Did you complete the replacement? | -- | -- | |
14 | Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 5.7 L. Did you complete the replacement? | -- | -- | |
15 | Perform the following procedure in order to verify the repair:
Has the test run and passed? | -- | System OK |
