P0474: Exhaust pressure sensor signal dropping in and out

Exhaust pressure sensor circuit intermittent

Severity: Severity not verified — if the car runs badly, have it inspected

The two sources read give a definition and causes but no guidance on how urgent the code is.

P0474 in short

P0474 means the engine computer found a problem with the exhaust pressure sensor circuit (intermittent signal). TroubleCodes.net lists the likely causes as a wiring fault, the sensor itself, or the engine computer. The code is a diagnostic title only, so a scan tool and wiring checks are needed to tell which one failed.

P0474 is a generic code titled "Exhaust gas pressure sensor - circuit intermittent" by the Delaware DMV list and by TroubleCodes.net.

Both sources describe a problem with the exhaust pressure sensor or its circuit; the code does not by itself say which part failed.

TroubleCodes.net says a basic scan tool reads the code but pinpointing the failed part needs more capable testing.

Most likely causes

These are general causes for this code across vehicles. None is specific to one make or model.

Cause 1: Wiring or poor connection in the sensor circuit
Common general cause
Why it ranks here
TroubleCodes.net lists wiring first among the causes for this code.
What would change this
Rises if the harness or connector shows damage or the reading changes when it is moved. Falls if wiring tests good.
Cause 2: Faulty exhaust pressure sensor
Common general cause
Why it ranks here
TroubleCodes.net lists the sensor itself as a cause; it ranks after wiring because the circuit is cheaper to check first.
What would change this
Rises if wiring and power tests good and the reading stays wrong. Falls if a known-good sensor reads normally.
Cause 3: Engine computer fault
Possible — needs testing
Why it ranks here
TroubleCodes.net lists the engine computer last; it is the least likely and is only suspected after the wiring and sensor are cleared.
What would change this
Rises only after wiring and sensor are proven good. Falls if either is found faulty.
How to test the engine control module (ecm / pcm)

What to test first

Start at step 1. Each result tells you what it means and where to go next.

Step 1: Read all stored codes and freeze-frame data with a scan tool and note whether other turbo, EGR or exhaust pressure codes are stored with P0474.
Low riskTool: OBD-II scan tool
- IfOther codes on the same circuit or system are stored
  It meansWork the shared wiring or power supply first.
  Go to step 2
- IfP0474 is the only code
  It meansInspect the sensor wiring next.
  Go to step 2
Step 2: With the key off, look over the sensor connector and harness for damage, corrosion, loose pins or rubbing.
Low risk
- IfDamage, corrosion or a loose pin is found
  It meansRepair the wiring or connector.
  Points to: Wiring or poor connection in the sensor circuit
- IfWiring looks fine
  It meansHave the sensor and computer checked.
  Go to step 3
Step 3: Have a shop check the sensor circuit with a multimeter or scope and compare the sensor reading with a reference.
Best left to a shopTool: multimeter, scan tool
Warning:Probing connectors can short pins and damage the computer, and the exhaust side is hot.
- IfCircuit tests good but the reading is wrong
  It meansThe sensor is suspect.
  Points to: Faulty exhaust pressure sensor
- IfSensor and wiring both test good
  It meansThe engine computer is suspect.
  Points to: Engine computer fault

Symptoms

Check engine light

How to fix

Step 1: With the engine off and cool, check the sensor connector and its wiring for damage or loose pins.

Parts and cost context

Engine control module (ECM / PCM):Rarely the cause; rule out wiring and the sensor first. Get a quote before buying parts.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

We don't have reviewed vehicle-specific evidence for P0474 yet. The causes and tests above apply across vehicles.

No curated relationships for P0474 yet.

All Diesel emissions and glow plugs codes

P0474 questions

What does P0474 mean?

It is the generic code for "Exhaust gas pressure sensor - circuit intermittent"; the likely causes are wiring, the sensor or the computer.

Sources and review

P0474 code page — TroubleCodes.net
On-Board Diagnostic Trouble Codes (generic code title list) — Delaware Division of Motor Vehicles

Last reviewed: October 16, 2026
Written by: Saurabh K.
Editorial review: Pending
Technician review: Technician review pending

This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error

Severity: Severity not verified — if the car runs badly, have it inspected

Most likely causes

Cause 1: Wiring or poor connection in the sensor circuit

Cause 2: Faulty exhaust pressure sensor

Cause 3: Engine computer fault

What to test first

Step 1: Read all stored codes and freeze-frame data with a scan tool and note whether other turbo, EGR or exhaust pressure codes are stored with P0474.

Step 2: With the key off, look over the sensor connector and harness for damage, corrosion, loose pins or rubbing.

Step 3: Have a shop check the sensor circuit with a multimeter or scope and compare the sensor reading with a reference.