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.
DTC P0453/16837 - EVAP System Pressure Sensor High Input
1996 Audi A4 Base, StandardSECTION DTC P0453/16837 - EVAP System Pressure Sensor High Input
NOTE:
DTC is set soon after engine start if EVAP differential pressure sensor signal is less than .1 volt for more than 2 seconds with EVAP emissions valve duty cycle more than 91 percent (100 percent equals valve closed).
- Inspect EVAP canister differential pressure sensor connector for looseness and/or corrosion. EVAP canister differential pressure sensor is located in right front corner of engine compartment. Repair sensor connector as necessary. If sensor connector was not repaired, go to next step. If sensor connector was repaired, erase DTC memory and test drive vehicle.
- Inspect EVAP system hoses between EVAP canister and throttle body. Repair hoses as necessary. If hoses were not repaired, go to next step. If hoses were repaired, erase DTC memory and test drive vehicle.
- Disconnect EVAP canister differential pressure sensor electrical connector. EVAP canister differential pressure sensor is located in right front corner of engine compartment. Turn ignition on. Using DVOM, check voltage on EVAP differential pressure sensor harness connector between terminals No. 1 (ground) and 3 (B+). Voltage should be approximately 5 volts. If voltage is within specification, go to step 7). If voltage is not within specification, go to next step.
- Turn ignition off. Disconnect Powertrain Control Module (PCM) connectors. Connect VAG 1598/19 test box to PCM wiring harness. Terminal assignments of test box are identical to PCM connectors "A", "B", "C", "D" and "E".
- Using DVOM, check for continuity between EVAP differential pressure sensor harness connector terminal No. 1 and test box socket C2. If continuity is present, go to next step. If continuity is not present, repair open or short in wiring harness as necessary. Erase DTC memory and test drive vehicle. If an open or short circuit cannot be located, replace faulty PCM. Code new PCM and test drive vehicle. See PCM CODING in this article.
- Using DVOM, check for continuity between EVAP differential pressure sensor harness connector terminal No. 3 and test box socket C6. If continuity is present, go to next step. If continuity is not present, repair open or short in wiring harness as necessary. Erase DTC memory and test drive vehicle. If an open or short circuit cannot be located, replace faulty PCM. Code new PCM and test drive vehicle. See PCM CODING in this article.
- Using DVOM, check for continuity between EVAP differential pressure sensor harness connector terminal No. 2 and test box socket B16. If continuity is present, circuit is okay. Replace EVAP differential pressure sensor. Erase DTC memory and test drive vehicle.
- If continuity is not present, repair open or short in wiring harness as necessary. Erase DTC memory and test drive vehicle. If an open or short circuit cannot be located, replace faulty PCM. Code new PCM and test drive vehicle. See PCM CODING in this article.
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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.