P0201 on Mercedes-Benz: Causes, Symptoms and Fix Cost

The Quick Answer above is the generic definition. What follows is the model-specific detail for the Mercedes-Benz models that log P0201.

Beyond the generic causes listed on the main P0201 page, these are the patterns noted for Mercedes-Benz models:

Follow these steps to pinpoint the root cause of P0201:

1. Read the code and its freeze frame with Skanyx, then check which other codes are stored: P0301 (cylinder 1 misfire), P0261 or P0262 (cylinder 1 injector circuit low or high) and P0200 (injector circuit general) each change where you look next
2. Find cylinder 1 before you unplug anything. On most engines it is at the crankshaft-pulley end, which on a transverse engine is the end away from the gearbox. Peugeot and Citroen engines have traditionally numbered from the flywheel end instead, so confirm with the service information for your engine
3. Follow the injector harness to the first connector at that end. Check the locking clip, look for green corrosion or pushed-back pins, and inspect the branch where it leaves the main loom for chafing against brackets or the cam cover
4. With the ignition off and the connector unplugged, measure across the two injector pins. Port-injection petrol injectors typically read about 12-17 ohms, while direct-injection and diesel injectors use much lower values, so compare against the figure for your engine
5. Measure again from the ECU connector pin for injector 1 so the reading includes the harness. A good injector at the plug but an open reading at the ECU pin points to the wiring between them
6. Swap injector 1 with injector 2, its neighbour on the same rail, clear the code and drive. If the fault moves to P0202 the injector is faulty; if P0201 comes back the wiring or ECU driver is the problem. Direct-injection injectors need new PTFE combustion seals every time they come out
7. On common-rail diesels do not swap injectors without re-entering each injector's correction code (IMA, IQA or C2i) for its new position. That coding, and per-injector balance values, are outside generic OBD2 and need a brand tool such as Carly, OBDeleven or XENTRY, or a workshop

Estimated repair costs for P0201 in EUR, compiled across makes. Expect Mercedes-Benz parts and labour towards the upper end of each range.

These codes are often seen alongside P0201 or point to related issues, on any make: