Code Definition

P1338 — CMP Sensor Bank 1 Open Circuit Or Short To B+

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

About P1338

P1338 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 P1338 is stored, the module has detected an open (broken or disconnected) electrical path in the monitored circuit; a short-circuit (voltage pulled to ground or to supply) in the monitored circuit; a bank-specific fault, meaning it applies only to one cylinder bank of a multi-bank engine; 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.

P1338 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

The bank 1 camshaft position sensor reports camshaft position to the Engine Control Module, which combines it with the crankshaft signal to identify cylinder 1 on its firing stroke, sequence the injectors and close the loop on variable valve timing. Most are hall effect sensors supplied with a reference voltage and a ground, returning a square wave that switches between near supply voltage and near ground as the trigger wheel passes. DTC P1338 covers two conditions on that circuit: an open circuit, where the module sees no signal at all because of a failed sensor, a disconnected connector or a...

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