Espar d2 problems

[danielmarsh]

I’ve been working for months trying to get my heater to work. When you turn it on, it does nothing. No fan, no pump, nothing. I checked the voltages and they’re good, and voltage on the control line as well. I checked the resistances on all of the parts that can cause it to not get to the fan running stage, the glow pin, heat sensors, and fuel pump. The glow pin was barely out of spec and the others were fine, so I replaced the pin and screen, but the problem remained.

If the pin doesn’t fix the problem the next thing is a bad or locked ecu, but I didn’t want to replace a locked ecu just because of that so I bought the code reader. It read lots of codes (even after clearing the codes they came back) glow pin short circuit, glow pin open circuit, theft protection short circuit, and bad ecu. Because of all that nonsense I replaced the ecu. It fixed every code but glow pin short circuit which remains.

So then I got to thinking, what if something else is shorting out but the pin is getting the blame? First I unplugged the pin and the code changed from short circuit to open circuit which makes sense. After looking at the wiring diagram I realized that the fan is switched on the negative side which means any negative short circuit will automatically apply power to the fan even if it has not been commanded by the ecu. So my theory is, ecu tells glow pin to turn on in the first moments of being switched on, but the fan short circuits, but since it has not switched on the fan, it thinks, glow pin short circuit since it just turned that on.

I unplugged the fan and got the fan interruption error, but the glow pin error went away! This is very interesting because the fan isn’t supposed to turn in until after the glow pin is tested, which means to get to that error the glow pin must pass its test.

Also, I had not realized that using diagnostic mode turns on the fan. The old ecu did not turn on the fan and the new ecu turns it on for a split second then shuts it down, which made me question the fan in the first place. It’s weird that it does not give a fan error however even though the operation is suspect.

So I wanted to post about this to see if anybody had any advice for me or had experienced this type of error before. I’m extremely hesitant about just replacing the same parts a second time just because that’s what the error code points to. Those parts weren’t cheap! My plan when I get back home is to remove the fan and bench test it, as well as compare to a new unit to the old one in operation.