P1403

Code

Other P — Powertrain

DPFE Sensor Hoses Reversed

Brand: Other

Type: P — Powertrain

Views: UK: 39 EN: 67 RU: 49

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Hoses to DPFE sensor connected to the wrong ports (reversed)
Incorrect routing after maintenance or hose replacement
Aftermarket or incorrect replacement hose assembly
Collapsed, cracked or internally clogged hose routed to opposite port
Service technician error during repair or component replacement

Symptoms

Check Engine MIL illuminated (DTC stored)
Poor idle or rough running when EGR is commanded
Reduced drivability or hesitation under part-throttle conditions
Reduced fuel economy and possible failed emissions test
EGR-related codes such as low or high EGR flow may also be present

What to check

Visually inspect DPFE sensor hoses for correct routing against vehicle-specific diagram
Check for split, collapsed, kinked or disconnected hoses
Verify connector is fully seated and no wiring damage to DPFE sensor
Scan tool: confirm P1403 is stored and view live DPFE sensor voltages/values and EGR command
Inspect EGR valve and passages for blockages that could have prompted prior service

Signal parameters

DPFE supply: typically 5 V reference and ground present at connector (verify vehicle-specific values)
DPFE output voltage normally in mid-range (~1–4 V depending on engine) and changes when EGR is commanded — values vary by manufacturer
Differential signal: one DPFE port voltage higher than the other; reversed hoses invert expected port voltages
Look for inconsistent or inverted live data compared with known-good reference or service data

Diagnostic algorithm

Read freeze frame and confirm P1403 is current; note related codes (EGR flow codes).
With ignition off, compare hose routing to factory vacuum diagram or repair manual — correct any hoses that are reversed.
Perform a visual inspection for damaged, collapsed or blocked hoses; replace any suspect hoses with correct-spec parts.
With scan tool, monitor DPFE sensor voltages or differential readings at idle and while commanding EGR (if vehicle allows). Verify response direction matches expected behavior.
If hoses appear correct but readings are still inverted, swap the DPFE sensor ports back to correct orientation and recheck readings.
If electrical supply or signal is missing or abnormal, check DPFE connector, harness continuity to PCM and reference voltage/ground (repair wiring as needed).
Clear codes, perform road test and re-scan to confirm P1403 does not return.
If problem persists after hoses and wiring are verified, test/replace the DPFE sensor per factory procedure.

Likely causes

Recent EGR, DPFE sensor, intake, or vacuum-hose service where hoses were reinstalled incorrectly
Use of non-original or mismarked vacuum lines leading to wrong connections
Damaged or collapsed hose that was rerouted during previous repairs

Fault status

⚠️ Status

P1403 — DPFE sensor hoses are reversed or connected to incorrect ports. The differential-pressure sensor is seeing reversed or incorrect pressures, causing improper EGR flow readings and triggering an EGR-related fault.

🟢 Repair difficulty: Easy

⏱️ Diagnostic time: 0.5-1.5 hours