Hi
I have just installed dashcommand for use with my wifi obd scanner and iphone; previously been using Rev.
Dashcommand gives me more sensor outputs (like lambda) but also IAT - which is constantly reading -40C?
Just wondering if anyone else has this issue, i.e it is a software problem, or if my IAT sensor is kaput. And if so, is it integrated into the MAFs?

 

The IAT is part of the MAFS, I believe. I use the Torque Pro app for Android, which is an excellent ODBII reader for quick code and sensor readings.

It seems that if your ECM really thought it was that cold outside, it would mess with the fuel settings, etc.



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It's part of the MAF but is a separate sensor with two wires.

I believe -40C is what you will see on an open circuit.

Before replacing the MAF, you might check the resistance of the sensor to make sure it's dead and also clean the MAF connector.

This is from the 2003 wiring diagram but I think the 2000MY is the same.

 

I guess that a low reading like -40C would make it think the air was denser, so presumably it would add fuel to compensate for having more air available. I have got high trim readings but only on one bank.
The MAF is a new one which has sorted my previous misfires on two cylinders! Fingers crossed it's the connector. I'll try a resistance check as well as putting the old one back in and seeing if that gives a sensible value.

 

I'm surprised your not getting a fault code.

 

Well, after checking, I have got a code for low voltage on the air temperature sensor recorded. But no retricted performance, CEL or strange engine behaviour.

I can't help wondering if it's the reader or app just getting it wrong; I would expect a whole lot of trouble if it really was reading that low.

 

If it looks faulty then the PCM will substitute a more plausible value but fuelling will be somewhat wrong. It'll somewhat correct using the O2s. The snag is that at WOT it can't use the O2s.

I'd just fix it

I can't see why to doubt the OBD tool as it appears to be giving consistent data but I suppose you could use (or pay someone to use) a better OBD tool and cross-check.

 

yep looks like I should just sort it!

 

Does this app read ABS codes?

 

It will read any code that's available through OBD-II; it's the live sensor data that's doubtful. I'm not sure though if ABS codes are part of the OBD protocol or CAN?

 

OBD is emissions. ABS is not part of that. Some tools, but only a few, do also read ABS.