P1599 — 6 documented meanings by make
Documented by: AUDI, CHEVROLET (USA), CHRYSLER, MERCEDES-BENZ, OPEL / VAUXHALL, SEAT, SKODA, VOLKSWAGEN — the meaning can differ between manufacturers
P1599 does not mean the same thing on every car — manufacturers reuse the number for different faults. 8 makes document it: Audi, Chevrolet (USA), Chrysler, Mercedes-Benz, Opel / Vauxhall, SEAT, Skoda, Volkswagen. Find your make below.
| Make | Documented meaning | Points at |
|---|---|---|
| Audi | Idle speed adaptation value above limit | signal too high |
| SEAT | Idle speed adaptation value above limit | signal too high |
| Skoda | Idle speed adaptation value above limit | signal too high |
| Volkswagen | Idle speed adaptation value above limit | signal too high |
| Chevrolet (USA) | Cruise control management | cruise control |
| Chevrolet (USA) | Engine stall or near stall detected | |
| Chrysler | Air-conditioning pressure sensor input voltage too low | signal too low |
| Mercedes-Benz | Ambient air temperature display temperature sensor | |
| Opel / Vauxhall | Engine stall detected |
P1599 on Audi, SEAT, Skoda, Volkswagen
On Audi, SEAT, Skoda, Volkswagen vehicles P1599 is documented as: Idle speed adaptation value above limit. P1599 is stored when the ECU sees signal too high on the circuit named in the code. That describes how the circuit is behaving, not which part has failed — the wiring, the connector and the component itself can all produce it, which is why the checks below start with the cheapest.
Usually one of: Open ground for the sensor, letting the signal float up; Signal line shorted to a supply voltage; Sensor failed open, which the module reads as maximum; Connector fault interrupting the return path.
Check first, cheapest first:
- Read the live value and compare with what the conditions should produce
- Check the sensor ground continuity back to the module
- Unplug the sensor: if the reading changes, the wiring is intact and the sensor is suspect
- Inspect the connector for corrosion or a spread terminal
- Replace the sensor once ground and signal wiring are confirmed good
Related Audi, SEAT, Skoda, Volkswagen codes:
P1599 on Chevrolet (USA)
On Chevrolet (USA) vehicles P1599 is documented as: Cruise control management; Engine stall or near stall detected. P1599 points at cruise control. The standard definition names the system involved; which part inside it has actually failed is what the checks below establish, cheapest first.
Related Chevrolet (USA) codes:
P1599 on Chrysler
On Chrysler vehicles P1599 is documented as: Air-conditioning pressure sensor input voltage too low. P1599 is stored when the ECU sees signal too low on the circuit named in the code. That describes how the circuit is behaving, not which part has failed — the wiring, the connector and the component itself can all produce it, which is why the checks below start with the cheapest.
Usually one of: High resistance in the supply or ground path, dragging the signal down; Corroded connector adding resistance the module reads as a low reading; Sensor drifted out of tolerance with age; Partial short to ground somewhere in the signal line.
Check first, cheapest first:
- Read the live value on a scanner and compare with a known-good reading
- Clean and re-seat the connector, then re-test before replacing anything
- Check the ground point for that circuit — a poor ground causes this far more often than a bad sensor
- Measure the sensor against specification with the connector back-probed
- Replace the sensor only once the wiring and ground have been ruled out
Related Chrysler codes:
Which one is yours
A generic OBD reader gives you the number, not which of these meanings your manufacturer assigned to it. To get to the specific one:
- Use a brand-specific scanner — VCDS for VAG, INPA or ISTA for BMW, XENTRY for Mercedes, Forscan for Ford. It shows the manufacturer's own text rather than the generic one.
- Read all stored codes together — the neighbouring ones usually point at which system is involved and narrow the list.
- Check freeze-frame data: the RPM, temperature and load at the moment it triggered indicate which system was active.
- If you have no brand scanner, tell me the make and model below and I will tell you which of these applies to your car.
Code family
P1xxx is manufacturer-specific code (VW/Audi, BMW, Mercedes, Toyota etc. have different meanings for the same code number).
Severity
Manufacturer-specific codes need a brand scanner (VCDS for VAG, INPA for BMW, STAR for Mercedes).
That is what holds for P1599 in general. From here it depends on your engine — tell me which car it is and what it does, and I will give you the steps for it: real procedures, torque figures and diagrams instead of general advice.
Why TorqFix for your car?
Above is what the code means and why it appears. TorqFix goes further — it gives you specific procedures, torque values, wiring diagrams and pinouts for your exact engine, not generic steps for every car. Real workshop data (127,000+ diagrams, 10,000+ procedures), interpreted by AI in your language.
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Code breakdown
Who makes these pages, and how
TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.
The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.
The same code can mean different things on different makes. Match the meaning to your make before acting on it.
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