P0503 Vehicle Speed Sensor 1 Erratic

P0503 Vehicle Speed Sensor 1 Erratic - This code will set if no vehicle speed signal is received from the ABS module for up to 120 seconds for 2 consecutive trips. When monitored with the ignition off. Battery voltage greater than 10.0 volts. Transmission in drive or reverse, The MIL light is illuminate.

Possible Causes P0503 Code

• Active BUS or communication DTC.
• Tire circumference.
• Powertrain Control Module (PCM).

Diagnostic test P0503 Vehicle Speed Sensor 1 Erratic

Step 1. Check for an active DTC

Turn the ignition on, with the scan tool, read DTC.

Check for any Bus communication DTC. If no Bus communication DTC are set, check for active DTC stored in the Antilock Brake Module (ABS). Any bus or communication DTC or VSS DTC in the ABS must be properly diagnose before continuing. Start the engine, allow the engine to reach normal operating temperature. With a scan tool, read DTC.

It may be necessary to drive the vehicle to meet the conditions to set this DTC, try to repeat the conditions in which the fault originally set by reviewing the freeze frame data.

Is the DTC active or pending?

YES, go to step 2.

NO, perform the the PCM intermittent condition.

Step 2. Visual Inspection

This code can set due to tire circumference differences and from the front or rear wheels being on a slippery surface while the opposite tires are not. This code may also set an a hard acceleration on loose gravel other off road driving conditions. Check tire pressure of all the tires. Check tire wear on all the tires. Ask the customer what the road  and driving conditions were like when the fault set.

Were any problems found?

YES, repair as necessary. If the code set during a front or rear wheel spin condition, no repair is necessary.

NO, go to step 3.

Step 3. Check related PCM and component connections

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