Full engine Power light

[Hib Halverson]

Originally Posted by SteveCanyon

When I turn the valet key to full power the full engine power light briefly illuminates then goes out. Is it supposed to be on all the time? It will come on and stay if I move the key to the stop and hold it, but if I release that pressure the light goes out. Car does not seem to be making full power. The first time I got on it the rpm stopped climbing and stopped at about 5.5K RPM and then got the Check Engine light.

Second, I hooked up my scanner and got codes 12, 55 & 65. Is code 55 Fuel Monitor lean, and code 65 Right O2 Sensor? If so, what should my trouble shooting process be from here?

I think rather than beginning the process by thowing parts at the problem (ie: arbitrarily replacing the fuel pumps), I'd get a copy of the factory service manual and run the tests and other diagnostic procedures for those two codes.

Why do I suggest that?

Well, 1) because it's how service techs go about solving problems and 2) you've got a strange situation with DTC 55 and 65 setting together. DTC55 is for lean exhaust when the secondaries are commanded open. DTC65 is for rich exhaust on the right bank.

Let's think for a minute. To set DTC55 the system has to be in closed loop and PE, the secondary pump has to be commanded on and either the right or left O2S has to indicate a lean exhaust for at least 2-sec.

But...DTC65 sets when the system is in closed loop, the throttle is less then 2.7% or more than 20% TPS for 30 seconds or more and the right bank runs rich for 30 seconds or more.

Seems strange to have the engine lean and rich at the same time.

Indeed, this could be a pump problem, but it also could be something else. Before I'd spend the bucks on a pump assembly and go to the trouble to change them, I'd run some tests out of the FSM to verify that the secondary pump is the problem.