Code Definition

P1159 — Mass airflow sensor banks 1 & 2 wrong ratio

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

About P1159

P1159 is a manufacturer-specific powertrain diagnostic trouble code recorded for Audi vehicles. It belongs to the P-prefix family of codes, which covers engine, transmission, emissions, or fuel-system faults.

When P1159 is stored, the module has detected a signal or supply voltage lower than the expected operating range; and a sensor-related fault — the reported value from the named sensor is out of spec.

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.

P1159 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

This code applies to engines fitted with two mass airflow (MAF) sensors, one measuring the intake air entering cylinder bank 1 and one measuring the air entering cylinder bank 2. The Engine Control Module (ECM) continuously compares the airflow reported by both sensors and expects them to stay within a close ratio of one another across all engine speed and load conditions. DTC P1159 is stored when the ratio between the two MAF signals falls outside the plausibility window, indicating that one sensor is reading incorrectly or that one bank is drawing an unequal volume of air. Because the ECM us...

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