P073E — Unable to Engage Reverse

P073E: Unable to Engage Reverse — what it means, the affected system and what to check before replacing parts.

Meaning, symptoms, causes and checks

The transmission control system reports that the gearbox could not engage reverse. The DTC identifies a failed engagement condition, not the particular component or repair required; diagnosis depends on the vehicle and transmission.

Affected system: Powertrain

Symptoms

  • Warning light may illuminate
  • Related system function may be impaired
  • Vehicle-specific symptoms vary

Possible causes

  • Implausible sensor or switch signal, poor ground, connector corrosion, or wiring damage
  • Related wiring, connector, power or ground fault
  • Vehicle-specific mechanical or control issue

What to check

  • Record stored and pending codes and freeze-frame data
  • Compare the named sensor or switch signal with actual operating conditions; inspect the connector, reference supply, ground and harness.
  • Confirm measured values against the vehicle service information
  • Retest under the conditions that set the code
  • Compare the named sensor or switch signal with actual operating conditions; inspect the connector, reference supply, ground and harness.
  • Repair the verified cause and confirm the code does not return

Also written as: P073E-00, P073E00, PO73E (some scan tools add the fault-type byte, e.g. -00).