HELP: Engine Shuts Off at Idle and While Driving

rykanotari

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Coworker has a 2012 Chevrolet Equinox with the Inline 4 Ecotec motor. They originally had a CEL for an INOP O2 Sensor. Code failed to specify if it was Sensor 1 or 2 so I replaced Upstream sensor for them. Code went away.

They popped another code a couple weeks later for the System running lean. I didnt have time to look at the car so they continued driving it around for a couple weeks. Then yesterday they were driving along and the engine sputtered then cut out on them. They had it towed home.

Any advice or help/info would be appreciated. I looked at it today and here were my findings (copy and paste of the email I sent them):

CEL Codes:

P0134 (O2 Sensor Circuit No Activity Detected Bank 1 Sensor 1)
P0171 (System Too Lean Bank 1)
P2A00 (O2 Sensor Circuit Range Performance Bank 1 Sensor 1)

Notes to Owner:

- We changed your Bank 1 Sensor 1 O2 sensor due to a different code. That code went away.
- Bank 1 Sensor 1 O2 sensor on Live Data reads >1.25 (max) voltage until the engine begins to warm up after cold start, then begins to read into the normal range. Thus your O2 sensor is working?
- MAF sensor reads within normal operating range on Live Data at idle and when depressing accelerator. Was also cleaned using MAF cleaner.
- Fuel Injector Cleaner was used and run through system.

Other Issues:

- Live Data shows FuelSys1 has an OL-Fault (Open Loop)
 

zora

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So the engine just started up and you were able to read codes.
Did you perform a fuel pressure test?
 

zora

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The P0134 has a number of causes that are not the actual sensor. Did you use an AC-Delco sensor?
Did you check the wire harness?

Bad O2 (oxygen) sensor
Bad heater circuit in the O2 sensor
Wiring or connector to the sensor frayed / broken
Blown heater circuit fuse
Holes in the exhaust system
PCM failure

The P0171 may be related to the P0134
The MAF (Mass Air Flow) Sensor is dirty or faulty Note: The use of "oiled" air filters may cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.
There could be a vacuum leak downstream of the MAF sensor
Possible cracked vacuum or PCV line/connection
Faulty or stuck open PCV valve
Failed or faulty oxygen sensor (bank 1, sensor 1)
Sticking/plugged or failed fuel injector
Low fuel pressure (possible plugged/dirty fuel filter!)
Exhaust leak between engine and first oxygen sensor

The P2A00 is also pointing to O2 related issue
A failed O2 sensor
Burnt, broken, or disconnected wiring and/or connectors
Engine misfires
Vacuum leaks
Bad mass air flow or manifold absolute pressure sensor
Engine exhaust leaks
 
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