Questions and Answers

Volvo 740 GLE DTC 3-2-1 Q. Mr. Ciulla, I have a 1990 Volvo 740 GLE. It was slow starting and then not at all. I used the process you described for a 1991 to check for codes but none of the codes listed fit. The DTC was 3-2-1 in socket #2. Also, could you please tell me where the sensor is located? Thank you for your help, Robert

Q. You have a 1991 Volvo 740 with the 'Regina/Rex-I' injection system. DTC 3-2-1 is "Signal to cold start injector missing or short circuit to ground".

The cold start injector improves the cold starting characteristics. It has a similar design to that of the injectors. In cold starts, a lot of fuel is condensed in droplet form on the cold surfaces. The cold start injector is thus located further away from the engine than the injectors and it supplies the fuel more in gas form than In droplet form.

The cold start injector is activated at approximately 1 C and at engine speeds under approximately 600 rpm. When one of the limits is exceeded, the cold start injector is shut. On certain models, the cold start injector is connected to the starter motor so that it can only be activated when the engine is started. On certain cars, voltage supply is connected to the starter motor so that injection can only take place when the engine is cranked. The engine speed and temperature limits are the same.

So basically what the code is saying is the signal from the computer is not getting to the cold stat injector, or the injector itself is bad. Use this wiring diagram to trace the wiring and check the injector. If they are good, then the computer may need to be replaced.

The cold start injector is located near the throttle drum on the intake manifold. It looks like an ordinary fuel injector.