GMC Sierra P1133:  Meaning, Causes, and Diagnosis

P1133 can have different definitions depending on the vehicle manufacturer in question.  In the case of the GMC Sierra it means: HO2S Insufficient Switching (Bank 1, Sensor 1) It is typically caused by a failure of the heated oxygen sensor.  But, there can be a few other causes as well.  They are all addressed below. … Read more

GMC Sierra U0073: Meaning, Symptoms, + Diagnosis

U0073 Definition: Control Module Communication Bus”A” Off U0073 is a fairly common trouble code.  It is generic, so it has the same meaning for your GMC Sierra as it would any other.  This code appears when something has interrupted the communication between two of your Sierra’s control modules. The most common causes of U0073 are … Read more

GMC Sierra P2276: B2S3 O2 Sensor Stuck Lean

P2276 is a general diagnostic trouble code.  It means that your GMC Sierra’s third (from the exhaust manifold) “bank 2” downstream oxygen sensor (behind the catalytic converter) is continuously sending voltage that indicates a lean air/fuel mixture.   Having this code does not necessarily mean that the vehicle is running lean (although it can, but … Read more

GMC Sierra P2274:  B1S3 O2 Sensor – Stuck Lean

P2274 in the GMC Sierra is a general diagnostic trouble code.  It means that the “bank 1” oxygen sensor (third oxygen sensor from the exhaust manifold, behind a catalytic converter) is continuously sending voltage that indicates a lean air/fuel mixture.   This does not necessarily mean that the vehicle is running lean (although it can, … Read more

GMC Sierra P2018:  Meaning + Diagnosis

P2018 is a generic diagnostic trouble code (DTC) that indicates an issue with your GMC Sierra’s intake manifold runner position sensor/valve (from here on out, we will be referring to this sensor by its common abbreviation of IMRC). P2018 Definition: IMRC – Switch Circuit Intermittent (Bank 1) IMRC The IMRC’s job is to help your Sierra’s … Read more

GMC Sierra P0356: Coil Pack “F” Malfunctioning – Diagnosis

P0356 is a generic OBD II diagnostic code that indicates an issue with the ignition coil “F” (the sixth cylinder). Specifically with the primary or secondary wiring circuits. If your GMC Sierra has thrown this code, it will usually be accompanied by P0306.  Addressing P0356 should take care of P0306 on its own. P0356 is a … Read more

P0355-GMC-Sierra

P0355 is a generic OBD II diagnostic code that indicates an issue with the ignition coil “E”. Specifically with the primary or secondary wiring circuits. If your GMC Sierra has thrown this code, it may be accompanied by P0305.  P0355 is a relatively straightforward diagnosis and is typically caused by a bad coil pack or wiring harness issue, although … Read more

GMC Sierra P2198: Meaning, Symptoms, Causes + Diagnosis

P2198 is a generic diagnostic trouble code that indicates that your GMC Sierra’s B2S1 O2 sensor signal is stuck rich. It does not necessarily mean that the vehicle itself is running rich (although it very well could). DTC P2198 is most likely caused by a bad oxygen sensor, although there are many potential secondary causes. … Read more

GMC Sierra P2138:  Symptoms, Meaning, Causes + Diagnosis

P2138 is a generic powertrain code that can affect your GMC Sierra’s “drive by wire” throttle system.  It means that your Sierra’s “D” and “E” throttle position sensors do not agree with one another on how much far the throttle has been opened.  They should have a similar voltage output.  In this case, they do … Read more

GMC Sierra P2196: Definition, Symptoms, Causes + Diagnosis

P2196 is a generic diagnostic trouble code that indicates that your GMC Sierra’s first oxygen sensor on bank one is stuck rich. It does not necessarily mean that the vehicle itself is running too rich.  This code is the opposite of code P2195, which indicates the oxygen sensor is stuck lean. P2196 Definition: Oxygen Sensor … Read more