OBD-II Fault Code Guide

P24AE Code: Particulate Matter Sensor Circuit
Causes, Symptoms & How to Fix

Published: May 14, 2026 Last Updated: May 14, 2026 Verified by iCarsoft Tech Team 12 min read
Quick Summary

P24AE means the PCM has detected a fault in the Particulate Matter (PM) sensor circuit — the sensor downstream of the diesel particulate filter (DPF) that monitors soot output. The most common fix is replacing the PM sensor ($150–$400 DIY) or repairing a damaged connector (often water ingress on the frame rail). You can drive short distances, but ignoring P24AE risks DPF damage costing $1,500–$3,000+. Always inspect connectors and harness before condemning the sensor.

P24AE — Quick Reference
Definition Particulate Matter (PM) Sensor Circuit
Severity Moderate–High — MIL on, emissions failure, DPF risk
Trigger Implausible signal from PM sensor circuit (open, short, or out-of-range)
Location Downstream of DPF, near the tailpipe / frame rail (diesel vehicles)
Common Vehicles Ram 1500 EcoDiesel, Jeep Grand Cherokee Diesel, VW TDI, BMW/Mercedes diesel
Related Codes P24B0, P24B1, P24C6, P2002, P2452, U02A3
DIY Fix Cost $150–$400 (PM sensor only)
Pro Fix Cost $400–$900 sensor; $1,500–$3,000 DPF
Recommended Tool iCarsoft CR MAX BT

What Does P24AE Mean?

When your Check Engine Light turns on and a scan shows P24AE, the PCM has detected a circuit malfunction in the Particulate Matter (PM) sensor — a key emissions component on diesel vehicles equipped with a Diesel Particulate Filter (DPF).

  • PM Sensor Role: Measures soot content in the exhaust after the DPF. Its purpose is to verify the DPF is trapping particulates correctly, not to control fuel mixture.
  • How It Works: Soot particles collect on inter-digital electrodes, forming conductive paths that drop electrical resistance. When a threshold is reached, the PCM signals a DPF regeneration cycle.
  • P24AE Specifically: A general circuit fault — the PCM cannot read a plausible signal from the PM sensor. Sub-codes like P24B0 (low) and P24B1 (high) narrow the issue further.
Key point: P24AE only appears on diesel vehicles with a DPF. If you see it on a gasoline car, the scanner is misinterpreting another code — recheck with a manufacturer-specific scanner.

Symptoms of P24AE

P24AE often appears without obvious drivability changes, but watch for these signs:

  • Check Engine Light (MIL) on — the primary indicator. Some vehicles also light the DPF warning lamp.
  • Failed emissions inspection — the PCM cannot verify DPF efficiency, which causes automatic OBD-II test failure.
  • Excessive exhaust smoke — if the DPF is also clogged, you may see visible black or grey smoke at acceleration.
  • Reduced engine power / limp mode — some vehicles derate engine power to protect emissions hardware, especially when paired with P2002 or other DPF codes.
  • Failed or incomplete regeneration cycles — without valid PM sensor data, the PCM cannot manage regen properly, causing soot accumulation.
Warning: Ignoring P24AE for extended periods can lead to DPF damage. A $200 sensor swap can escalate to $2,000+ DPF replacement if regeneration is disrupted long enough.

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What Causes P24AE?

Five primary causes, ordered by real-world frequency from forum reports and dealer data — work through them in sequence:

1

Failed PM Sensor — Most Common

The PM sensor element degrades over time. High exhaust temperatures, soot saturation, and thermal cycling kill the internal electrodes. Accounts for roughly 50–60% of P24AE cases, especially over 80K miles.

2

Connector Water Ingress / Corrosion

On Ram EcoDiesel and Jeep Grand Cherokee Diesel, the PM sensor connector sits on the frame rail and is prone to water intrusion — especially after a car wash. A very common, cheap-to-fix culprit.

3

Damaged or Chafed Wiring Harness

The harness routing near the exhaust can rub through, causing short circuits or open circuits. Reported especially on vehicles with aftermarket exhausts or after off-road use.

4

Clogged DPF / Failed Regeneration

If the DPF is heavily loaded with soot, the PM sensor may read implausible values. Often paired with P2002 (DPF efficiency below threshold). Frequent short trips accelerate this.

5

DEF System or Upstream Fault — Less Common

A clogged DEF injector, faulty NOx sensor, or upstream exhaust leak can cause the PM sensor to read out of range. Inspect the broader emissions system if codes persist after sensor replacement.

Quick Diagnosis Decision Path — What codes do you see?

You have P24AE — which other codes appear?
↓
Branch A: P24AE + P2002
→ Suspect DPF FailureBoth the sensor and DPF likely need replacement. Force a regen first — if soot levels don't drop, the DPF is finished.
Branch B: P24AE + U02A3
→ Communication FaultU02A3 = lost communication with PM sensor module. Check connector, harness, and module power before replacing the sensor.
Branch C: P24AE Only
→ Connector First, Sensor SecondInspect frame-rail connector for moisture and corrosion. Clean and re-seat before buying a sensor.

How to Diagnose P24AE — Step by Step

Systematic diagnosis saves serious money on this code — the PM sensor itself can cost $400–$700 OEM. Follow these steps before buying parts:

1
Confirm the Code & Read Freeze-Frame

Connect a scanner that supports diesel-specific codes (generic OBD-II often shows only P24AE without sub-codes). Record all companion codes (P24B0, P24B1, P2002, U02A3) and capture freeze-frame data — engine RPM, exhaust temp, DPF soot load, and miles since last regen.

2
Inspect the Frame-Rail Connector First

This is the #1 fix on Ram and Jeep EcoDiesel vehicles. Unplug the PM sensor connector (often near the frame rail, behind a clip). Look for moisture, green corrosion, or a connector pulled off its mounting clip. Clean with electrical contact cleaner, re-seat firmly, and apply dielectric grease.

Pro tip: Many owners report P24AE appears right after an automatic car wash. If that matches your timing, water in the connector is almost certainly the cause.
3
Inspect the Wiring Harness

Trace the harness from the PM sensor to its module. Look for: rub-through points near the exhaust or chassis; cracked insulation from heat damage; melted sections (common after exhaust leaks near the DEF injector). Even a tiny short to ground will trigger P24AE.

4
Check DPF Soot Load & Force a Regen

Using a capable scan tool, read DPF soot load percentage. If soot is above 75%, the DPF is nearing capacity and the PM sensor may read implausibly. Initiate a forced (parked) regeneration — if soot levels drop normally and P24AE clears, the issue was regen-related.

5
Test the PM Sensor & Module

With the engine off and cool, disconnect the sensor and measure heater circuit resistance against OEM service data. Verify supply voltage at the connector (typically 12V) with the key on. Out-of-range values confirm sensor or module failure.

6
Clear the Code & Verify the Repair

After repair, clear all codes and complete a long highway drive cycle (30+ minutes at sustained 50+ mph) — this allows the PM sensor self-test to run and trigger a regen if needed. Re-scan after 100 miles. If P24AE doesn't return and DPF monitors show "Ready," the repair is confirmed.

Understanding PM Sensor Data — Live Diagnostics Guide

Unlike O2 sensors, PM sensors don't output a continuous voltage — they cycle through measurement and regeneration phases. Here's how to interpret what you see:

PM Sensor & DPF Soot Load — Interpretation

Normal DPF Soot Load0% – 45% (healthy)
0–45%
Regen Triggered45% – 70%
45–70%
High Soot — Forced Regen Needed75% – 90%
75–90%
Critical — DPF Damage RiskAbove 95%
> 95%

* Soot load thresholds vary by manufacturer. Verify against your OEM service data.

If the PM sensor reports "no signal" or stays at 0% across multiple drive cycles: The sensor or its module has failed internally. This is the strongest indicator for sensor replacement.

How to Fix P24AE

Option 1: Clean & Reseal the Connector (Try First)

A $0–$10 fix that resolves many P24AE cases — especially on Ram and Jeep EcoDiesel models. Unplug the PM sensor connector, dry thoroughly, clean terminals with electrical contact cleaner, apply dielectric grease, and re-seat firmly. Verify the clip is secured to prevent the connector from hanging loose.

Option 2: Replace the PM Sensor

Allow exhaust to cool fully. Apply penetrating oil to the threaded bung 15 minutes before removal. Use an oxygen-sensor-style socket. Torque to OEM spec (typically 40–55 Nm). Use only OEM or Bosch sensors — cheap aftermarket PM sensors frequently trigger re-faults within weeks.

Option 3: Repair Damaged Wiring

Splice out the damaged section using heat-shrink solder connectors. Re-route the harness away from heat sources and abrasion points. Secure with high-temp loom and zip ties. Address the root cause (rub point, melted section) or the fault will return.

Option 4: Force DPF Regeneration

If soot load is high but the DPF still functions, a forced parked regen via scan tool can restore normal operation. Drive 30+ minutes at sustained highway speed afterward. Repeated forced regens, however, indicate the DPF is failing and will need replacement.

Option 5: Replace the DPF or PM Sensor Module

A last-resort fix when soot load remains high after regen, when P2002 is also present, or when the sensor module itself fails. DPF replacement is expensive but necessary if the filter is irreversibly clogged.

Repair Cost Breakdown

Repair DIY Cost Professional Cost Time
PM Sensor Replacement — Most Common $150–$400 $400–$900 45–90 min
Connector Cleaning / Repair $0–$30 $100–$300 30–60 min
Wiring Harness Repair $15–$50 $150–$500 1–3 hrs
Forced DPF Regeneration Tool needed $100–$250 30–60 min
DPF Replacement $1,000–$2,000 $1,500–$3,000+ 3–5 hrs
Delay risk: A neglected P24AE can disrupt DPF regeneration, turning a $200 connector fix into a $3,000 DPF replacement. Diagnose connectors and wiring before assuming the sensor has failed.

Diagnose P24AE Yourself with iCarsoft CR MAX BT

Basic code readers can't run diesel-specific functions. The CR MAX BT gives you full DPF and PM sensor diagnostics in your hand:

  • 7-inch HD touchscreen with diesel-specific PIDs
  • DPF soot load & regen status live monitoring
  • Forced DPF regeneration support (where supported)
  • Freeze-frame capture for intermittent faults
  • Reads manufacturer sub-codes (P24B0, P24B1, U02A3)
  • Code clearing + readiness monitor verification
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P24AE on Common Vehicle Makes

P24AE is exclusively a diesel-vehicle code. These makes show the highest reported frequency:

Ram EcoDiesel Very Common

  • Especially Ram 1500 EcoDiesel (2014–2019, 60K+ miles)
  • Primary cause: frame-rail connector water ingress
  • Clean and reseal the connector before buying a sensor

Jeep Grand Cherokee Diesel Very Common

  • Frequent on 2014–2016 Grand Cherokee EcoDiesel
  • Many cases covered under emissions warranty (10yr / 120K miles) — check before paying out-of-pocket
  • Harness chafe is a secondary cause

VW / Audi TDI Common

  • Reported on Golf TDI, Jetta TDI, Passat TDI, A3, Q5
  • Often combined with P24C6 (temperature circuit)
  • Bosch OEM PM sensor recommended

BMW / Mercedes Diesel Common

  • BMW 335d, X5 35d; Mercedes BlueTEC range
  • Often paired with regen-frequency complaints
  • Sensor module replacement may be required

Ford / GM Diesel Moderate

  • Ford F-250/350 Power Stroke, Chevy/GMC Duramax
  • Inspect harness near turbo and exhaust manifold
  • Forced regen often clears the code temporarily

Other Diesels Global

  • Reported on Vauxhall/Opel, Peugeot, Citroën, Land Rover, and Mazda diesel models with DPF/PM sensor systems.

How to Prevent P24AE

  • Avoid frequent short trips — diesels need long highway runs (20+ minutes at sustained speed) to complete DPF regeneration. Short trips load soot faster than the system can burn it off.
  • Inspect frame-rail connectors twice a year — apply dielectric grease and verify clip integrity. This single habit prevents most P24AE cases on Ram and Jeep EcoDiesel.
  • Use the correct DEF and high-cetane diesel fuel — poor-quality fuel and DEF accelerate soot production and can gel inside DEF injectors, indirectly triggering P24AE.
  • Scan proactively every 3 months — check for pending codes and DPF soot load. Catch issues before the Check Engine Light triggers.
  • Address P24AE within 1–2 weeks — delayed repairs can disrupt regen cycles and damage the DPF, escalating cost dramatically.

P24AE often appears alongside these codes — knowing the combination helps pinpoint the root cause:

P24B0
PM Sensor Circuit Low — narrows P24AE to a low-side fault
P24B1
PM Sensor Circuit High — narrows P24AE to a high-side fault
P24C6
PM Sensor Temperature Circuit — heater-related fault
P2002
DPF Efficiency Below Threshold — often paired with P24AE
U02A3
Lost Communication with PM Sensor Module

Frequently Asked Questions About P24AE

Can I drive with P24AE? ▾
Yes, but only short-term. The vehicle may run normally at first, but DPF regeneration can be disrupted, leading to soot accumulation and potential DPF damage. Diagnose and fix within 1–2 weeks.
Is P24AE serious? ▾
Yes, moderate-to-high severity. While drivability is often unaffected initially, prolonged operation risks DPF damage, limp mode, and automatic emissions test failure. Some manufacturers will derate engine power if soot accumulates excessively.
Will replacing the PM sensor always fix P24AE? ▾
Not always. While a failed sensor causes about 50–60% of cases, a corroded frame-rail connector, chafed harness, or clogged DPF can all trigger P24AE. Inspect the connector first — it's the most overlooked fix.
How much does it cost to fix P24AE? ▾
PM sensor replacement runs $400–$900 professionally, or $150–$400 DIY. Connector repair is often under $30. DPF replacement, if required, costs $1,500–$3,000+. Always diagnose connectors before assuming the sensor is bad.
Is P24AE covered under warranty? ▾
On many US-market vehicles, emissions components — including the PM sensor — are covered under federal emissions warranty (8 years / 80,000 miles, sometimes longer on certain Ram/Jeep models). Always check with your dealer before paying out-of-pocket.
Can I pass emissions with P24AE? ▾
No. P24AE triggers the Check Engine Light and indicates an emissions-related fault, causing automatic OBD-II inspection failure. You must repair the issue, clear the code, and complete a full drive cycle before retesting.
Why did P24AE appear after a car wash? ▾
This is a very common pattern on Ram EcoDiesel and Jeep diesel models. Water enters the PM sensor connector on the frame rail, causing temporary short circuits. Clean, dry, and reseal the connector — often the only fix needed.
Can a clogged DPF cause P24AE? ▾
Yes. A heavily clogged DPF (above 75% soot load) can produce implausible PM sensor readings. Force a regeneration first — if soot levels normalize and P24AE clears, the issue was regen-related, not a sensor failure.
How long does it take to fix P24AE? ▾
Connector cleaning takes 30–60 minutes. PM sensor replacement runs 45–90 minutes for a DIY mechanic with the right tools. Wiring harness repair can take 1–3 hours depending on access. A shop visit typically lasts half a day.
What cars most commonly get P24AE? ▾
P24AE is most frequently reported on Ram 1500 EcoDiesel, Jeep Grand Cherokee Diesel, VW/Audi TDI models, BMW 335d/X5 35d, Mercedes BlueTEC diesels, and Ford/GM heavy-duty diesels — all vehicles equipped with a DPF and PM sensor.

Verified by iCarsoft Automotive Technicians

This guide is based on diesel emissions diagnostics data, dealer service bulletins, and thousands of real-world cases from Ram, Jeep, VW, and BMW diesel platforms. Our technicians review all content to ensure accuracy and help owners avoid unnecessary parts replacement.

Wrap-Up

P24AE is a manageable diesel emissions fault when approached methodically. In most cases — especially on Ram EcoDiesel and Jeep platforms — the fix is a connector cleaning rather than a sensor swap. The key is to check the cheap stuff first before spending hundreds on parts.

  • Always inspect the frame-rail connector before buying a sensor
  • Check DPF soot load — force a regen if above 75%
  • Verify your vehicle's emissions warranty coverage before paying
  • Address P24AE within 1–2 weeks to protect the DPF

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Disclaimer: This guide is for reference only. Always verify diagnostic procedures, torque specifications, and sensor compatibility against the OEM service manual for your specific vehicle. iCarsoft Technology Inc. is not responsible for any vehicle damage resulting from repairs performed without proper training or equipment.