Damaged, chafed or corroded wiring to the exhaust pressure sensor; Loose, corroded or contaminated sensor connector terminals; Failing exhaust pressure sensor; Blocked, split or leaking sensing pipe or hose to the sensor (where fitted); Wiring damage caused by heat or vibration near the exhaust or turbocharger; Fault in the engine control unit or its power and ground supplies.

P047E

Exhaust Pressure Sensor B Circuit Intermittent/Erratic.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
4: AreaAuxiliary emission controls
7E: FaultThe specific fault in that area

What it means

P047E is the generic code for an intermittent or erratic signal from exhaust pressure sensor 'B' circuit. The engine control unit has seen the sensor's voltage or signal jump, drop out or behave implausibly compared with expected values or other inputs. Which bank or position 'B' refers to varies by model and engine, so check the manufacturer's information.

Symptoms

Engine warning light on
Reduced power or limp mode
Poor or hesitant acceleration
Turbocharger boost or variable geometry control behaving oddly
Rough running or uneven idle
Particulate filter regeneration problems or related fault codes

Possible causes

Damaged, chafed or corroded wiring to the exhaust pressure sensorlikely
Loose, corroded or contaminated sensor connector terminalslikely
Failing exhaust pressure sensorlikely
Blocked, split or leaking sensing pipe or hose to the sensor (where fitted)possible
Wiring damage caused by heat or vibration near the exhaust or turbochargerpossible
Fault in the engine control unit or its power and ground suppliesrare

How to diagnose

Read all stored and pending codes and note freeze frame data such as engine speed, load and temperature at the time the fault set.
Check for related codes covering other exhaust pressure sensors, boost, particulate filter or sensor supply voltage, as these can point to a shared cause.
Locate sensor B using the model-specific information and visually inspect the sensor, wiring and connector for heat damage, chafing, oil, water or corrosion.
Check any sensing pipe or hose for blockage, cracks, soot build-up or leaks, where the engine uses one.
With the engine running, view live exhaust pressure data and gently wiggle the harness and connector to see if the reading drops out or jumps.
Test the sensor's supply, ground and signal wires for continuity, shorts and voltage drop against the manufacturer's specification.
Compare the live reading with key-on engine-off and with other pressure readings to judge whether the sensor output is plausible.
Check for exhaust leaks near the sensor, as these can disturb readings and cause erratic values.

How to fix

Repair or replace damaged wiring and secure the harness away from heat and sharp edges.
Clean or replace corroded connector terminals, or renew the connector.
Replace the exhaust pressure sensor if it is faulty or its signal remains erratic after wiring checks.
Clear or replace a blocked or damaged sensing pipe or hose.
Repair any exhaust leak affecting the sensor reading.
Only after all other causes are excluded, diagnose and repair the control unit or its supplies per manufacturer procedure.

Can I keep driving?

Medium severity

The car can usually be driven carefully for a short time, but power may be reduced and the fault could affect boost control or filter regeneration. Have it checked soon, and stop if power loss becomes severe or warning lights flash.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.