Code B337 - Loss Of HVAC Programmer Data: Notes

Code B337 will set if the ignition is on and the BCM has lost data communication with the programmer. The fault could be due to a loss of 12 volts power or ground to the programmer or a double open in the programmer data line, one on each side of the component. When this code is set the A/C clutch is disabled and the blower runs at a constant 6 volts.

1. First check that the code is not intermittent.
2. This step determines if the fault is due to the power or ground circuits or the data line.
3. This step determines if the data line fault is due to the wiring or the programmer.
4. This step checks for ignition-3 to the programmer.
5. This step determines if the loss of ground is due to the programmer, wiring or the CPS.