Loose, corroded, or intermittently connected electrical connector at the exhaust pressure sensor; Chafed or damaged wiring harness between the sensor and the PCM, often near hot or moving components; Failing exhaust pressure sensor that loses signal when hot or vibrating; Clogged or restricted exhaust pressure sensor tube or port, causing erratic pressure readings; Water or debris intrusion into the sensor or connector, leading to intermittent shorts; PCM internal fault or software glitch affecting the sensor signal circuit; Poor ground connection shared by the sensor circuit

DTC codes / P04xx · Auxiliary emission controls / P0474

P0474Exhaust Pressure Sensor Intermittent

Q: What does code P0474 mean?

Exhaust Pressure Sensor Intermittent. P0474 means the powertrain control module (PCM) has seen the exhaust pressure sensor signal drop out or become erratic intermittently, rather than failing completely. The PCM monitors the sensor's voltage or data stream and flags this code when the signal is present most of the time but momentarily disappears or glitches beyond a calibrated threshold.

P0474 means the powertrain control module (PCM) has seen the exhaust pressure sensor signal drop out or become erratic intermittently, rather than failing completely. The PCM monitors the sensor's voltage or data stream and flags this code when the signal is present most of the time but momentarily disappears or glitches beyond a calibrated threshold.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaAuxiliary emission controls

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Intermittent or momentary loss of power or hesitation under load
Rough running or surging during acceleration
Reduced fuel economy or increased regeneration frequency on diesel vehicles
A stored freeze-frame showing the fault occurred under specific conditions such as high exhaust temperature or vibration
Occasional hard start or stall, especially on diesel engines with exhaust aftertreatment

Common causes, most likely first

Loose, corroded, or intermittently connected electrical connector at the exhaust pressure sensor
Chafed or damaged wiring harness between the sensor and the PCM, often near hot or moving components
Failing exhaust pressure sensor that loses signal when hot or vibrating
Clogged or restricted exhaust pressure sensor tube or port, causing erratic pressure readings
Water or debris intrusion into the sensor or connector, leading to intermittent shorts
PCM internal fault or software glitch affecting the sensor signal circuit
Poor ground connection shared by the sensor circuit

How to diagnose and fix it

Inspect the exhaust pressure sensor connector and wiring for looseness, corrosion, or damage; clean and secure as needed
Check the sensor tube and port for blockage or carbon buildup; clear any restriction
Perform a wiggle test on the harness while monitoring live sensor data to reproduce the intermittent fault
Measure sensor reference voltage and ground at the connector; compare with manufacturer specifications
Replace the exhaust pressure sensor if signal dropouts are confirmed and wiring is intact
Repair or replace damaged sections of the wiring harness
Clear the code and verify the repair with a road test and live data monitoring

Intermittent faults hide in connectors and heat

Many technicians replace the exhaust pressure sensor only to find the real fault is a chafed wire that shorts only when the engine bay is hot or the vehicle hits a bump.
A clogged sensor tube can cause the sensor to read atmospheric pressure intermittently, setting P0474 without any electrical fault at all.
This code often appears alongside P0470, P0471, or P0472, and diagnosing those first can reveal whether the sensor or its circuit is the root cause.
On diesel vehicles, exhaust pressure sensor faults can disrupt the diesel particulate filter (DPF) regeneration strategy, leading to secondary codes and reduced performance if ignored.
A failing sensor may test perfectly when cold, so always monitor live data during a test drive that includes the conditions stored in freeze-frame.

Can I keep driving with P0474?

You can usually continue driving to a workshop, but avoid heavy acceleration, towing, or long uphill pulls until the fault is repaired. If the engine enters limp mode or you notice repeated regeneration attempts, stop driving and seek professional diagnosis.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.