Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Normal Operation and Fault Conditions
The ABS module uses a sensor mounted on the brake booster to monitor booster vacuum. The vacuum on-demand system keeps the brake booster vacuum at a predetermined level. When a low vacuum condition is detected by the ABS module, a message is sent to the PCM. The PCM responds by grounding the aspirator valve and allowing air to flow out of the brake booster, creating additional vacuum in the booster. An aspirator valve failure or an aspirator valve circuit fault results in the PCM setting a DTC. A hard brake pedal may also be present when one of these DTCs is set.
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| P103C | Aspirator Valve Control Circuit/Open | This DTC sets in the PCM if the aspirator valve control circuit is open, the valve is open internally or there is no voltage being supplied to the valve. |
| P103D | Aspirator Valve Control Circuit Low | This DTC sets in the PCM if the aspirator valve control circuit is shorted to ground or the valve is shorted internally. |
| P103E | Aspirator Valve Control Circuit High | This DTC sets in the PCM if the aspirator valve control circuit is shorted to voltage or the valve is shorted internally. |
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.