P24B7 – Particulate Filter Temperature Sensor Circuit High

P24C7: Particulate Matter Sensor Temperature Circuit Range/Performance

The P24C7 diagnostic trouble code (DTC) indicates a problem with the particulate matter (PM) sensor temperature circuit in diesel vehicles equipped with a diesel particulate filter (DPF). This article provides a comprehensive technical overview of the P24C7 code for automotive engineers and mechanics.

Code Urgency and Immediate Actions

The P24C7 code is generally considered a moderate severity issue. While it may not cause immediate drivability problems, it should be addressed promptly to prevent potential damage to the exhaust aftertreatment system. Continued driving is usually possible, but it's recommended to have the vehicle inspected by a qualified technician as soon as feasible. If other symptoms like reduced power or excessive exhaust smoke are present, limit driving and seek immediate repair.

Detailed Code Information

P24C7 specifically relates to the temperature circuit of the particulate matter sensor. This indicates that the powertrain control module (PCM) has detected a problem with the PM sensor's temperature reading or circuit performance. The code is typically used across multiple vehicle manufacturers, though exact diagnostic criteria may vary slightly.

Components Involved

Particulate Matter Sensor

The PM sensor is located in the exhaust system, typically after the diesel particulate filter. It measures soot levels in the exhaust to determine DPF efficiency and loading. The sensor contains:

• Interdigital electrodes (IDE) for soot detection
• An internal heater element
• A temperature sensor to monitor and control sensor operation

Temperature Circuit

The temperature circuit monitors and controls the PM sensor's operating temperature, which is critical for accurate soot measurements. It typically operates in the range of 200-300°C (392-572°F).

Related Components

• Diesel Particulate Filter (DPF)
• Exhaust Gas Temperature (EGT) sensors
• Engine Control Module (ECM)

Common Causes

1. Faulty PM sensor (most common)
2. Damaged wiring or connectors in the PM sensor circuit
3. Exhaust leaks affecting sensor readings
4. ECM/PCM software issues
5. Extreme carbon buildup on the sensor element

Diagnostic Procedure

1. Connect an OBD-II scanner and verify the P24C7 code.
2. Check for other related DTCs, particularly exhaust system codes.
3. Inspect the PM sensor and wiring for visible damage or contamination.
4. Use a multimeter to check the sensor's heater circuit resistance. Typical values range from 3-7 ohms at 20°C (68°F).
5. Measure the temperature sensor circuit resistance. Expected values vary by manufacturer but are typically in the 100k-500k ohm range at 20°C (68°F).
6. Use a scan tool to monitor PM sensor temperature PID. Compare to exhaust gas temperature sensor readings for consistency.
7. Perform a voltage drop test on the PM sensor power and ground circuits.

Solutions and Repair Options

• Replace the PM sensor if internal faults are confirmed
• Repair or replace damaged wiring and connectors
• Update ECM/PCM software if a known issue exists
• Clean excessive carbon buildup using specialized equipment (if applicable)

Prevention Strategies

• Follow recommended DPF regeneration procedures
• Use high-quality diesel fuel and engine oil
• Perform regular exhaust system inspections
• Address any engine performance issues promptly

Cost Analysis

• Diagnostic time: 1-2 hours ($75-$300)
• PM sensor replacement: $200-$600 (€170-€510) for parts
• Labor costs: $100-$300 (€85-€255) for sensor replacement
• Total repair cost estimate: $300-$900 (€255-€765)

Related Issues and Fault Codes

• P24C6: PM Sensor Circuit Malfunction
• P24AE: PM Sensor Voltage Circuit Low
• P24AF: PM Sensor Voltage Circuit High
• P229F: NOx Sensor Circuit Range/Performance

By understanding the intricacies of the P24C7 code, automotive professionals can efficiently diagnose and repair particulate matter sensor issues, ensuring optimal performance of diesel exhaust aftertreatment systems.

Frequently Asked Questions About P24B7

What does the P24B7 code mean?

P24B7 indicates a problem with the Particulate Matter Sensor Heater Resistance in diesel vehicles equipped with a diesel particulate filter (DPF).

How serious is the P24B7 code?

This issue is not critical yet, but should be addressed soon to prevent more severe problems. You can continue driving, but have it checked as soon as feasible.

What causes the P24B7 code?

Common causes include a faulty particulate matter sensor, damaged wiring or connectors, exhaust leaks, or excessive carbon buildup on the sensor.

What are the symptoms of P24B7?

There may be no noticeable symptoms other than the check engine light. In some cases, you may experience reduced engine performance or increased exhaust smoke.

Can I drive with the P24B7 code?

Yes, you can typically continue driving, but it’s recommended to have the issue diagnosed and repaired soon to prevent potential damage to the exhaust system.

How is P24B7 diagnosed?

Diagnosis involves scanning for codes, inspecting wiring and connectors, testing the particulate matter sensor’s resistance and signals, and checking for exhaust leaks.

What parts are commonly replaced to fix P24B7?

The most common replacement part is the particulate matter sensor itself. In some cases, wiring harnesses or connectors may need repair or replacement.

How much does it cost to fix P24B7?

Repair costs can vary, but typically range from $300 to $900 (€255 to €765), including parts and labor for sensor replacement.

Can I fix P24B7 myself?

While possible for experienced DIYers, it’s generally recommended to have a professional diagnose and repair this issue due to the specialized equipment and knowledge required.

How long does it take to fix P24B7?

Diagnosis typically takes 1-2 hours, with repair time varying based on the specific issue. Sensor replacement usually takes 1-3 hours.

Will P24B7 clear itself?

It’s unlikely that P24B7 will clear itself. The underlying issue needs to be addressed for the code to be permanently cleared.

What vehicles commonly experience P24B7?

This code is most common in diesel vehicles with DPF systems, particularly in certain Ford, BMW, and other European diesel models.

Is P24B7 covered under warranty?

Coverage depends on your specific warranty terms. Some manufacturers have extended coverage for particulate matter sensor issues.

What other codes are related to P24B7?

Related codes include P24C6 (PM Sensor Circuit Malfunction), P24C7 (PM Sensor Temperature Circuit Range/Performance), and P229F (NOx Sensor Circuit Range/Performance).

How can I prevent P24B7 from occurring?

Regular maintenance, using high-quality diesel fuel, and addressing any engine performance issues promptly can help prevent this code.

What is the function of the particulate matter sensor?

The PM sensor measures soot levels in the exhaust to determine DPF efficiency and loading. It’s crucial for proper emissions control system operation.

Where is the particulate matter sensor located?

It’s typically located in the exhaust system, after the diesel particulate filter.

How accurate is the P24B7 code?

P24B7 is generally accurate in indicating a problem with the PM sensor heater circuit, but further diagnosis is needed to pinpoint the exact cause.

Can a clogged DPF cause P24B7?

While a clogged DPF itself doesn’t directly cause P24B7, it can contribute to excessive soot buildup on the PM sensor, potentially leading to this code.

What happens if I ignore the P24B7 code?

Ignoring P24B7 could lead to inaccurate DPF monitoring, potentially causing DPF damage, reduced fuel efficiency, and increased emissions over time.