Diesel Trouble Codes

P0471 — Exhaust Pressure Sensor A Circuit Range/Performance (6.7 Cummins (SCR / DEF))

Exhaust Pressure Sensor A Circuit Range/Performance

Updated September 2, 2026

What it means

The powertrain control module has detected that the exhaust pressure sensor A signal is outside the expected range or is performing inconsistently. On the 6.7L Cummins SCR/DEF platform this is the exhaust pressure sensor used for DPF differential pressure monitoring and regeneration control.1

Most likely causes

  1. Exhaust pressure sensor A internal failure or drift — Sensor output is out of range or slow to respond; typical range/performance fault.1
  2. Wiring/connector fault to exhaust pressure sensor A — Chafed, corroded or loose harness/connector causing intermittent or biased signal.1
  3. Exhaust pressure sensor A supply/ground voltage issue — Reference voltage or ground drop causing out-of-range reading.1
  4. Exhaust pressure sensing lines/tubing restriction or leak — Clogged or leaking pressure signal tubing to the sensor gives false pressure reading.1
  5. DPF/exhaust restriction causing actual pressure out of expected range — High backpressure from a plugged DPF or exhaust blockage can drive sensor reading beyond calibrated range.1
  6. PCM calibration or software anomaly — Incorrect sensor scaling or software glitch causing range/performance detection.1

How to diagnose

  1. Verify freeze-frame and repeatability of P0471; check for accompanying DPF/regeneration or exhaust codes.
  2. Inspect exhaust pressure sensor A connector and wiring for corrosion, chafing, moisture; repair as needed.
  3. Check sensor supply voltage and ground per service information; confirm stable reference.
  4. Remove and inspect pressure signal tubing for blockage, cracks, or moisture; blow through or replace.
  5. Command sensor reading with scan tool and compare to a known-good sensor or substitute; evaluate response to pressure changes.
  6. Inspect DPF and exhaust for restriction; review differential pressure data during idle and loaded conditions.
  7. If electrical and mechanical checks pass, reprogram/verify PCM calibration per latest TSBs.

Parts and tools you may need

Rough cost and difficulty

Parts and labor vary by model year and shop; sensor and tubing are relatively low cost, but diagnosis time can increase if wiring or DPF restriction is involved.

When to see a pro

If wiring faults are found in the engine bay or exhaust area, or if DPF restriction is suspected, have a qualified diesel technician perform inspection and testing. Do not disassemble high-temperature exhaust components without proper training and equipment.

Sources

  1. Curated DTC seed — 6.7 Cummins (SCR / DEF) (curated) ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎