Code Definition

P1170 — Bank to Bank Fuel Trim Offset

System: Powertrain  |  Type: Manufacturer-Specific  |  Make: GM

About P1170

P1170 is a manufacturer-specific powertrain diagnostic trouble code recorded for GM vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

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.

P1170 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

On V configuration engines the Engine Control Module (ECM) calculates fuel trim separately for each cylinder bank and continuously compares the two sets of values against each other. DTC P1170 is set when the fuel trim for bank 1 and the fuel trim for bank 2 differ by more than the calibrated offset threshold for an extended period, indicating that one bank is running significantly richer or leaner than the other. Because the ECM cannot correct both banks with a single fuelling strategy once they diverge, this code points to a bank specific fault such as an intake leak, a biased or lazy oxygen...

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