Code Definition

P2188 — System Too Rich At Idle Bank 1

System: Powertrain  |  Type: Generic (OBD-II Standard)  |  Make: Generic

About P2188

P2188 is a generic (obd-ii standard) powertrain diagnostic trouble code. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P2188 is stored, the module has detected a bank-specific fault, meaning it applies only to one cylinder bank of a multi-bank engine.

Scanning & clearing: A generic OBD-II scan tool will usually read and clear powertrain (P) codes. For live data, freeze-frame capture, and bi-directional tests you may need a more capable scan tool that supports the vehicle's ECM protocol.

Because P2188 is a generic OBD-II code, its base definition is shared across manufacturers. The specific diagnostic steps, reference values, and repair procedures can vary by vehicle, and the TaT Diagnostic Assistant includes verified procedures submitted by working technicians.

Code Information

The ECM holds the mixture close to stoichiometric using feedback from the upstream oxygen or air fuel ratio sensor, trimming injector pulse width through short term and long term fuel trim to compensate for variation. DTC P2188 is set when the ECM must subtract a substantial amount of fuel at idle on bank 1, with fuel trim driven well negative, commonly beyond about 10 percent, before the mixture returns to range. Bank 1 is always the bank containing cylinder number one, and on inline and four cylinder engines it is the only bank, which means on those engines this code represents a whole engin...

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