Schematic Reference: Engine Controls Schematics
Circuit Description
The Vehicle Speed Sensor (VSS) is mounted on the transaxle. As the transaxle turns the VSS, the VSS provides the speedometer with a vehicle speed input (voltage pulses). This input is used to drive the speedometer. The speedometer then converts the vehicle speed input into a more precise signal and provides the Powertrain Control Module (PCM) and the Cruise Control Module with its own vehicle speed input. The PCM converts this input (ground pulses) into a vehicle speed.
Conditions for Setting the DTC
Manual transaxle Vehicle
No vehicle speed sensor signal to PCM, when the vehicle speed is above 3 mph.
Automatic Transaxle Vehicle
| • | Park/Neutral position switch is "OFF." |
| • | Vehicle speed is above 3 mph. |
Action Taken When the DTC Sets
| • | The PCM will illuminate the MIL. |
| • | The PCM will store the conditions which were present when the DTC set as Freeze Frame Data. |
Conditions for Clearing the MIL/DTC
| • | The PCM will turn the MIL "OFF" on the third consecutive trip cycle during which the diagnostic has been run and the fault condition is no longer present. |
| • | A DTC will clear after 40 consecutive warm-up cycles have occurred without a fault. |
| • | A DTC can be cleared by using the scan tool "Clear Information" function or by disconnecting the PCM battery feed. |
Diagnostic Aids
| • | A scan tool should indicate a vehicle speed whenever the drive wheel is turning greater than 3 mph (5 km/h). DTC P0500 can be falsely set if the engine is "brake-torqued" in gear. Disregard if set while the drive wheels are not turning. |
| • | An intermittent malfunction may be cause by a poor connection, rubbed through wire insulation, or a broken wire inside the insulation. Inspect harness connectors for backed out terminals, improper matting, broken locks, terminal-to wire connection before component replacement. |
| • | The information included in the Freeze Frame data can be useful in determining the vehicle operating conditions when the DTC first set. |
| • | Check G202 for a clean and tight connection. |
Test Description
The numbers below refer to the step numbers in the Diagnostic Table.
-
The OBD System Check prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.
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Checks whether the PCM is receive a signal from the vehicle speed sensor.
-
This step checks whether DTC P0500 is the result of a hard failure or an intermittent condition.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Was the "Powertrain On Board Diagnostic (OBD) System Check performed? | -- | |||
Does scan tool display vehicle speed above the specified value? | 0 mph | |||
Does DTC P0500 set? | -- | Go to Diagnostic Aids | ||
4 | Does the vehicle speedometer operate? | -- | ||
5 |
Does the DMM read within specified value? | 4-6 V | ||
6 |
Does DMM vary in voltage within specified range? | 0-5 V | ||
7 |
Does DMM read more than specified value? | 10 V | ||
8 | Probe the VSS connector cavity 2 with a test light connected to battery voltage Does the test light illuminate? | -- | ||
9 | Using a DMM, measure voltage at instrument cluster connector C3 cavity 12. Does the DMM read more than specified value? | 10 V | ||
10 |
Important: All 3 connectors to instrument cluster must be plugged in. Does DMM vary in voltage within specified value? | 0-10 V | ||
11 |
Was a repair necessary? | -- | ||
12 | Check for an open or short in the ignition power feed between VSS and junction block 1. Is the action complete? | -- | -- | |
13 |
Was a repair necessary? | -- | ||
14 | Check for an open or short between ignition power feed and junction block 3. Is the action complete? | -- | -- | |
15 |
Was a repair necessary? | -- | ||
16 |
Did printed circuit need replacement? | -- | ||
17 | Replace the VSS. Is the action complete? | -- | -- | |
18 | Replace the speedometer. Is the action complete? | -- | -- | |
19 | Replace the instrument cluster printed circuit. Is the action complete? | -- | -- | |
20 | Replace the PCM. Is the action complete? | -- | -- | |
21 | After repairs, use the scan tool clear information function and road test vehicle within "Freeze Frame" conditions that set the DTC. Check for DTC(s). Review scan tool data and if no DTC(s) are stored repair is complete. Are any DTC(s) displayed on scan tool? | -- | Go to the applicable DTC table | System OK |
