P2519
A/C Request A Circuit
A/C & idle control
Generic OBD-II
Low
What it means
P2519 means the ECM detected a fault in the air-conditioning "A" request circuit — the signal that tells the engine the A/C compressor wants to run so it can raise idle and switch on the cooling fans. It's an electrical/comfort-system fault: the A/C may not engage, but the engine runs normally.
Low
Can I keep driving? Fine to drive — this is an air-conditioning request signal fault. The A/C may not work or the idle may not adjust for it, but the engine runs normally.
Common symptoms
What you'll notice
- Check-engine light on
- Air conditioning not engaging or blowing warm
- Idle doesn't rise to compensate when A/C is switched on
- Cooling fans not commanding on with A/C
Common causes
Most likely first
- Faulty A/C request signal from the HVAC control or pressure switchLikely
- Open or shorted wiring in the A/C request circuitCommon
- Corroded or loose connector at the switch or ECMCommon
- Faulty A/C pressure switch/sensor sending the requestLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and confirm the fault is on the A/C request 'A' circuit.
- Check that refrigerant charge and pressures are within range (low charge can inhibit the request).
- Inspect the request-circuit wiring and connectors for opens, shorts, and corrosion.
- Test the A/C pressure switch/sensor and the request signal reaching the ECM.
- Repair the wiring or replace the faulty switch, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P2519?+
Yes. It only affects the air-conditioning request and related idle-up; the engine itself runs fine. You may simply lose A/C until it's fixed.
Can I just clear P2519?+
It will come back the next time the ECM checks the A/C request circuit unless the wiring or switch is repaired.
Related codes
Often seen with P2519
Read & clear P2519 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX