Mercedes-Benz W201 cold start injector not working
W201 will not start cold – what causes a cold start injector fault?
Often the injector gets no electricity. The cause may be weak solder joints in the overvoltage protection relay (YJ relay) behind the battery or a blown 10 A fuse, or an oxidised and loose injector connector. A clogged or stuck injector is also possible.
How is the W201 cold start injector tested?
The test is done cold. Measure the voltage at the injector connector during cranking. If it has 12 V and the injector does not spray, the injector is probably faulty. If no voltage arrives, the fault is in the wiring, relay or thermo time switch. Keep fuel and electrical wires apart, because it is dangerous.
What controls the W201 cold start injector and where is it?
The injector is in the intake manifold between cylinders 2 and 3. Its control runs through the thermo time switch: at −20 °C the injector is on for 12 s after starting, at +3 °C only 0.3 s.