I may have overlooked this section in the manual, or just forgot.. I noticed a thread this week discussing the exhaust overheat light in relation w/ the PFC. From what I understand, if the ECU is storing codes it now illuminates the exhaust overheat light upon startup rather than flashing the check engine light like the stock ECU? Does the light stay on or only for a second? How are stored codes retrieved now with the PFC? Thanks for any help..

Matt
93 SSM

and one last thing, under the etc menu it gives a readout of sensor voltages.. what can I check these against to make sure everything is within spec? The workshop manual?

 

Check against the manual. I had problems with my car stalling out when warm. Turned out that the water temp thermosensor was bad. But it wasn't bad enough to light the Exhaust warning light. After I changed the sensor all was well. Check the voltages, and if necessary, put the stock ecu back in to check for codes.

eric

 

The PFC doesn't store codes in the same way the stock ECU does. The PFC constantly monitors all of the sensors and will illuminate the Exhaust Overheat light if something is wrong. When you see that, you can check their status by going into the Etc, Sensor Check screen on the Commander. The voltage values for most of the sensors can be found in section F of the FSM.

 

jr:

Thanks for the reply, it all makes much more sense now. But when the Exhaust Overheat light is lit up does it stay lit up while the car is on/running?

Matt

 

Excellent question, I don't know the answer for sure, but my best guess would be that it will remain on till the problem is fixed. The PFC also uses that light and the CE light to warn of other dangerous conditions. Conditions like boost going over your preset limit, or over the MAP sensors 1.2 Bar limit, it will also light if the knock reading is sustained at 60 or higher for any length of time. When those things occur it will flash one of those lights, the PFC manual will tell you exactly which light will illuminate and in which flash pattern for which problems.

 

You cannot depend on the exhaust overheat light. When my sensor went out, it did not light up AT ALL. But when I put the stock computer back in, it threw the code. I then put the power FC back in, and checked the voltage. The sensor was bad enough to throw the code on the stock computer, and be off versus the FSM, but not bad enough to light up the Exhuast warning light. So either put the stock computer back in, or check the voltages of the sensors.

eric

 

Under the ETC; Sensor / Switch check the PFC also monitors the Exhaust Temp Warning switch. (HWL) My light on the console doesn't light up, but neither does the security light. Those two never have worked.
When I forgot to reattach one my other sensors the HWL did come on.