P0474

Exhaust Pressure Sensor A Circuit Intermittent/Erratic

Q: Is it safe to drive with P0474?

Short-term yes — the engine still starts and runs. On diesels the code can trigger reduced-power mode intermittently, which is safe but inconvenient, so repair it soon.

Q: Can I just clear P0474?

You can, but an intermittent fault like this usually returns. The 'intermittent/erratic' label means you'll likely need to catch it by wiggle-testing the wiring.

Exhaust / emissions Generic OBD-II Medium

What it means

P0474 means the exhaust pressure (back-pressure) sensor "A" is sending an intermittent or erratic signal to the ECM. This sensor helps manage EGR flow and, on diesels, DPF regeneration. The cause is usually a failing sensor, a loose connector, or wiring that breaks contact as it moves. The engine still starts and runs, though diesels may briefly enter reduced-power mode.

Medium

Can I keep driving? Yes — the car starts and drives. On diesels it may occasionally drop into reduced-power (limp) mode, so plan to get it fixed.

Real-world scan data

Seen in

scans in the past year

Found in

<0.1%

of scans

<0.1%

of scans that found faults

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
Occasional reduced power or limp mode (common on diesels)
Slightly reduced fuel economy
Possible rough or erratic running under load

Common causes

Most likely first

Faulty exhaust pressure (back-pressure) sensor ALikely
Intermittent break, chafe, or short in the sensor wiringCommon
Loose or corroded electrical connector at the sensorCommon
Blocked or cracked pressure sensing tube/portLess often
ECM fault (rare)Less often

How to diagnose & fix

Work through it in order

Read freeze-frame data and watch the sensor's live signal while wiggling the harness to catch the intermittent fault.
Inspect the connector and wiring for corrosion, loose pins, or chafing.
Check the sensor's sensing tube/port for blockage, soot, or cracks.
Test the sensor's signal against spec and replace it if erratic.
Repair wiring or replace the sensor, then clear and re-test.

FAQ

Quick answers

Is it safe to drive with P0474?+

Short-term yes — the engine still starts and runs. On diesels the code can trigger reduced-power mode intermittently, which is safe but inconvenient, so repair it soon.

Can I just clear P0474?+

You can, but an intermittent fault like this usually returns. The 'intermittent/erratic' label means you'll likely need to catch it by wiggle-testing the wiring.

Read & clear P0474 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX