What Does P0202 Code Mean?

OBD-II Code P0202 is defined as a Injector Circuit Malfunction - Cylinder 2

The purpose of the Fuel Injectors on either a gas or diesel engine is to spray vaporized fuel into the combustion chambers. This spray of fuel mixes with incoming air and is ignited to provide power in each of the engines cylinders by providing downward force on the pistons. 

Code P0202 sets when the Power Train Control Module or PCM sees an open or short in the #2 cylinder injector circuit.

P0202 Symptoms

  • Check Engine Light will illuminate
  • Failure of Emissions Inspections due to MIL malfunction
  • Failure of Emissions Inspections due to elevated emissions
  • Vehicle may run rough and misfire
  • Poor Fuel Economy
  • In rare cases, there are no adverse conditions noticed by the driver

Common Problems That Trigger the P0202 Code

  • Malfunction of the Fuel Injector
  • Malfunction of the PCM Fuel Injector driver circuit
  • Defective wiring/connections in the Fuel Injector wiring harness
  • Defective Fuel Injector power circuit(s)

Common Misdiagnoses

  • Spark plugs are replaced when the root cause is a defective Fuel Injector
  • Spark plugs are replaced when the root cause is a defective wiring harness

P0202 Diagnostic Theory for Shops and Technicians When inspecting for the cause of a Fuel Injector circuit malfunction, I start by looking at the freeze frame data to get a picture of when the malfunction occurred. After I've looked at the freeze frame data I visually inspect the injector and its wiring. If it looks intact I measure the resistance of the Fuel Injector to determine whether or not it's within specification and check for power at the injector while cranking the engine. If the Injector is out of spec I recommend replacing it. Then I do a functional test of the injector circuit by substituting a Noid Injector Test light in place of the Fuel Injector. The Noid light should blink crisply when the engine is started or cranked over. If the Noid light does not blink, I check the Fuel Injector harness for continuity by performing resistance tests on the power and ground portions of the harness while it is DISCONNECTED from the PCM and with the key OFF. If there is continuity in the Injector harness, I check the performance of the PCM's output transistor with a lab scope while cranking the engine. You want to see a crisp square wave that indicates the PCM is grounding the Injector circuit at the proper time.

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