EVAP code diagnosis

[smayfield]

Hi... I just replaced the fuel injectors on my 2002 Aztek (258k miles). After re-assembling everything, the car barely runs, usually stalling out right away, occasionally revving pretty high if I tap on the gas... check engine light came on and I pulled 2 codes from it... P0108 (MAP/Barametric Pressure Circuit High Input) and P0453 (EVAP Emissions System Pressure Sensor Switch High)... I recently did a head gasket replacement and most of the evap related hoses are brand new... I swapped in a new MAP sensor, but no effect. Before the fuel injector swap, the engine actually ran fine (minus a miss on cylinder 4 and a fuel injector circuit open code, which I diagnosed down to an injector wasn't plugged in completely). After the FI replacement, that FI open circuit code went away, but now I have these 2 EVAP codes. Any though on what I might have put together incorrectly that would result in these two codes together? I'm assuming it's user error at this point.

 

[melsg5]

The P0453 causes no symptoms.

P0453 DTC Evaporative Emissions Control System Pressure Sensor High Input

Detailed information on diagnosing and repairing a P0453 DTC trouble code which refers to Evaporative Emissions Control System Pressure Sensor High Input. Also includes links to relevant forum topics on the code.

www.obd-codes.com

The P0108 is not an evap code but it will cause your issues, vacuum leak or broken wire is a guess.

P0108 Manifold Absolute Pressure/Barometric Pressure Circuit High Input

Detailed information on troubleshooting and repairing a p0108 trouble code which refers to a high input in the maf sensor circuit. Also includes links to relevant forum topics on the code.

www.obd-codes.com

 

[smayfield]

@melsg5, I think you hit the nail on the head... I had someone else run the car and I heard the tell-tale whistling of a vacuum leak. Narrowed it down to the rear of the engine and I pulled the PVC Throttle Body to Valve Cover pipe and found the rear seal on it was damaged. Got a new one one the way. TNX!

 

[melsg5]

Good to hear you found the cause

______________________________

 

[smayfield]

Just circling back to update..... that throttle body pipe was bad, but not the actual cause.... I ended up tearing it down to the upper intake and found the upper intake to lower intake gasket was out of alignment and leaking like crazy... replaced that and it ran mostly normal... still have the code after clearing, but it seems to run fine... shortly there-after, I blew the rear brake line, so I'm working on that now...