DL50 - Code 336 or 337: Check For EVR Malfunction

- Diagnostic Trouble Code (DTC) 336 or 337 indicates that Differential Pressure Feedback EGR (DPFE) circuit voltage is higher than expected at zero duty cycle.

Possible causes are:

- Damaged EGR Vacuum Regulator (EVR) solenoid.

- Damaged DPFE sensor.

- Damaged or contaminated EGR valve.

- Vacuum hose routing.

- Damaged Powertrain Control Module (PCM).

- Key "OFF".

- Disconnect EGR valve vacuum line at valve and plug line.

- Rerun Key On Engine Running (KOER) Self-Test. Key ON Engine Running (KOER) Self-Test

- Is DTC 336 or 337 present (ignore all other DTCs)?

Yes -- Reconnect EGR vacuum line. Go to DL51. DL51 - Check DPFE Signal Voltage With Engine At Idle

No -- Verify vacuum line routing is correct. Check EVR filter for contamination or blockage. If all OK, replace EVR solenoid. Reconnect all lines. Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)