Ram Cummins · Exhaust Pressure SensorMedium

Ram Cummins P0473: Exhaust Pressure Sensor High

P-Code 0473 (FMI N/A) — Exhaust Pressure Sensor High

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Quick Answer

P0473 on the Ram Cummins means the exhaust pressure sensor circuit voltage is above the PCM maximum. Unplug the sensor and test the harness for a short to power before replacing the sensor.

Overview: Ram Cummins P-Code 0473

P0473 on the 6.7L Cummins flags a high-voltage condition on the exhaust backpressure sensor circuit that the PCM cannot use for EGR and DPF strategies. ProfessionalDieselRepair.com separates wiring shorts from failed sensors by backprobing the harness with the connector disconnected — the distinction saves a needless parts swap on most P0473 diagnoses.

Repair Snapshot

Time

1 - 2 Hours

Difficulty

Intermediate

Parts Cost

$60 - $280

Dealer Labor

$300+

Tools Required

  • Cummins INSITE
  • Diesel Laptops Diagnostic Software
  • Multimeter
  • Mechanical Wire
  • Basic Hand Tools

What P-Code 0473 Means

P0473 on the Ram Cummins 6.7L means the exhaust backpressure sensor signal voltage is above the PCM acceptable maximum. This high-input fault often results from a short to voltage in the signal wire, a failed sensor pulling the line high, or a disconnected pressure tube causing an implausible reading the PCM interprets as circuit high.

Symptoms Drivers Notice

  • Check engine light with exhaust pressure PID pegged high in Cummins INSITE or Diesel Laptops
  • Possible reduced EGR effectiveness or altered DPF regen behavior
  • No immediate derate in most cases unless paired with other aftertreatment faults
  • Companion codes P0470, P0471, or P0472 may be stored with related pressure circuit issues
  • Sensor voltage may read near battery voltage at the connector during backprobe testing

Most Likely Root Causes

Signal wire short to voltage in the engine harness

Very Common

Chafed wiring near the turbo and exhaust routing can contact a power feed, pulling the sensor signal to battery voltage.

Failed exhaust pressure sensor internal short

Common

A sensor that internally shorts the signal line high produces the same voltage the PCM flags as P0473.

Disconnected or damaged pressure sense tube

Moderate

Loss of pressure reference can drive the sensor output to an implausible high value on some 6.7L calibrations.

Common Misdiagnoses (Don't Waste Parts)

Parts-cannon sensor replacement when the harness signal wire is shorted to power

Why it happens: P0473 is read as a bad sensor by default without isolating the circuit.

Do this instead: Unplug the sensor and measure signal voltage at the harness. High voltage with the sensor removed confirms a wiring repair, not a sensor swap.

Ignoring P0473 because the truck still drives normally

Why it happens: High circuit faults often lack obvious drivability symptoms.

Do this instead: Repair the circuit promptly. Inaccurate backpressure data affects EGR and DPF regen decisions over time.

Master Tech Commentary

Mechanic's Notes

Shop tip: ProfessionalDieselRepair.com disconnects the exhaust pressure sensor and rechecks signal voltage at the harness on P0473 calls. If voltage stays high with the sensor unplugged, the fault is in the wiring — not the sensor. A parts-cannon sensor swap on a shorted harness wastes time and money.

Step-by-Step Diagnostic Procedure

  1. Step 1: Pull P0473 with Cummins INSITE or Diesel Laptops and note exhaust pressure sensor voltage at idle. Values near 5V or higher with low actual backpressure confirm a high circuit condition.
  2. Step 2: Inspect the pressure sense tube for disconnection or damage. A disconnected tube can cause erratic or maximum sensor output on some 6.7L configurations.
  3. Step 3: Disconnect the sensor connector and measure signal voltage at the harness side with key on. Voltage present on the signal wire with the sensor unplugged indicates a short to power in the harness.
  4. Step 4: Measure sensor signal voltage with the connector attached at idle. Compare to Cummins specification — typically well below reference voltage at low exhaust pressure.
  5. Step 5: Replace the exhaust pressure sensor if the harness tests clean but the sensor still pulls the signal high. Repair any chafed wiring found near the turbo and exhaust manifold.

Live Data & Freeze-Frame Tips

In Cummins INSITE or Diesel Laptops, monitor exhaust pressure sensor voltage alongside calculated backpressure at idle and under load. At idle, voltage should be low with modest backpressure. A voltage reading near reference supply with low actual pressure confirms P0473 root cause in the circuit or sensor.

Safety Warnings

  • Allow exhaust components to cool before disconnecting the pressure sensor or tubes.
  • Avoid piercing wire insulation when backprobing — use proper piercing probes or T-pins.

When to Limp In vs Tow

P0473 alone does not require towing unless paired with severe aftertreatment derate codes.

Prevention Tips for Fleets & Owner-Operators

  • Inspect harness routing near the turbo for rubbing during scheduled service.
  • Secure pressure sense tubes to prevent disconnection from vibration.
  • Address exhaust pressure codes early before soot loading affects related systems.

Related Fault Codes

P0472

Exhaust pressure sensor low — opposite voltage extreme on the same circuit.

P0470

General exhaust pressure sensor malfunction — may set alongside P0473.

P0401

EGR flow insufficient — can be influenced by inaccurate backpressure data.

Frequently Asked Questions

What does P0473 mean on a Ram Cummins?

P0473 means the exhaust pressure sensor signal voltage is higher than the PCM expects. The fault is a high-input circuit condition, not necessarily a physical exhaust restriction.

How do I test for a wiring short on P0473?

Disconnect the sensor and measure voltage on the signal wire at the harness with key on. Voltage near battery or 5V reference with the sensor unplugged indicates a harness short, not a failed sensor.

Can a clogged pressure tube cause P0473?

A disconnected or damaged tube can cause implausible readings on some trucks, but a true high-voltage short is more common. Always verify tube integrity and harness voltage together.

Does P0473 cause derate on 6.7L Cummins?

P0473 alone rarely causes derate, but it can affect EGR and DPF strategies. Companion codes may produce more severe limits if left unresolved.

Which scan tools diagnose P0473 on Cummins?

Cummins INSITE provides exhaust pressure sensor voltage and calculated backpressure on 6.7L Ram trucks. Diesel Laptops offers equivalent live data and fault clearing.

How much does P0473 repair cost?

Harness repair may run $100-$250 depending on damage location. Sensor replacement is typically $60-$150 plus one to two hours labor at a diesel shop.

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