P220C – NOx Sensor Circuit High

Urgency and Severity

The P220C code indicates an issue with the NOx sensor supply voltage circuit for Bank 2 Sensor 1. While not immediately critical, this fault should be addressed promptly to maintain proper emissions control and prevent potential engine performance issues. The code is considered moderately serious, as it can affect the vehicle's ability to accurately monitor and control exhaust emissions.

Continued Driving Safety

It is generally safe to continue driving for a short period with this code present. However, prolonged operation may lead to increased emissions, reduced fuel efficiency, and potential damage to the catalytic converter. It's advisable to have the issue diagnosed and repaired as soon as possible to prevent further complications.

Code Meaning and Significance

P220C specifically refers to a problem with the supply voltage circuit for the NOx (nitrogen oxides) sensor located after the catalytic converter on Bank 2 of the engine. This sensor is crucial for monitoring the efficiency of the exhaust aftertreatment system and ensuring compliance with emissions regulations. The code indicates that the sensor's supply voltage is outside the expected range, which can lead to inaccurate NOx readings and improper emissions control.

Code Specificity

P220C is a generic powertrain code applicable to various manufacturers using OBD-II systems. However, the specific diagnostic and repair procedures may vary depending on the vehicle make and model.

Components Involved

The main components associated with P220C include:

1. NOx sensor (Bank 2 Sensor 1)
2. Engine Control Module (ECM)
3. Wiring harness and connectors
4. Exhaust aftertreatment system

The NOx sensor measures the concentration of nitrogen oxides in the exhaust stream, providing crucial data for the ECM to adjust engine operation and ensure proper emissions control.

Common Causes

Typical causes of P220C include:

1. Faulty NOx sensor
2. Damaged wiring or connectors
3. ECM malfunction
4. Exhaust leaks
5. Failed catalytic converter

Diagnostic Procedure

1. Connect an OBD-II scanner and verify the P220C code.
2. Check for additional related codes.
3. Inspect the NOx sensor and its wiring for visible damage or corrosion.
4. Use a digital multimeter to measure the supply voltage at the NOx sensor connector. It should typically be between 12-14 volts.
5. Check the resistance of the sensor's heater circuit.
6. Perform a voltage drop test on the NOx sensor circuit.
7. Inspect the exhaust system for leaks or damage.
8. Use a scan tool to view live data from the NOx sensor and compare it to specifications.

Solutions and Repair Options

1. Replace the faulty NOx sensor if diagnosed as defective.
2. Repair or replace damaged wiring and connectors.
3. Update ECM software if available.
4. Replace the catalytic converter if it has failed.
5. Repair any exhaust leaks.

Preventive Measures

1. Regular maintenance of the exhaust system
2. Prompt repair of exhaust leaks
3. Using high-quality fuel
4. Avoiding prolonged idling
5. Regular engine tune-ups

Estimated Repair Costs

• Diagnostic fee: $100-150 / €85-130
• NOx sensor replacement: $200-500 / €170-425
• Wiring repair: $100-300 / €85-255
• ECM software update: $100-200 / €85-170
• Catalytic converter replacement: $500-2000 / €425-1700

Total costs can range from $200 to $2500 (€170 to €2125) depending on the specific issue and required repairs.

Repair Guide

1. Disconnect the vehicle's battery.
2. Locate the faulty NOx sensor (typically near the catalytic converter).
3. Disconnect the electrical connector.
4. Unscrew the sensor using a specialized socket or wrench (typically 22mm or 7/8").
5. Clean the mounting area and threads in the exhaust pipe.
6. Install the new sensor, torquing to manufacturer specifications (usually 20-40 Nm or 15-30 ft-lbs).
7. Reconnect the electrical connector.
8. Reconnect the battery.
9. Clear the fault codes and perform a test drive to ensure proper operation.

Related Issues and Fault Codes

P220C may be associated with other codes such as:

• P220B (NOx Sensor Circuit Range/Performance Bank 2 Sensor 1)
• P229F (NOx Sensor Circuit Intermittent Bank 2 Sensor 1)
• P2200-P2209 (NOx Sensor Circuit Malfunction)
• P20EE (SCR NOx Catalyst Efficiency Below Threshold)

These codes often indicate broader issues with the exhaust aftertreatment system or engine management, requiring a comprehensive diagnostic approach.

Frequently Asked Questions About P220C

What does the P220C code mean?

P220C indicates an issue with the NOx sensor supply voltage circuit for Bank 2 Sensor 1. Specifically, it means the Engine Control Module (ECM) has detected a problem with the voltage supply to this NOx sensor.

How serious is the P220C code?

While not immediately critical, P220C should be addressed promptly as it can affect emissions control and engine performance if left unresolved. It's considered moderately serious.

Is it safe to continue driving with a P220C code?

You can drive for a short period, but it's best to have the issue diagnosed and repaired soon to prevent potential damage or decreased performance. Limit driving to essential trips only.

What are the common symptoms of P220C?

Symptoms may include illuminated check engine light, decreased fuel efficiency, rough idling, and potentially reduced engine performance. In some cases, there may be no noticeable symptoms.

What causes the P220C code?

Common causes include a faulty NOx sensor, damaged wiring or connectors, corroded terminals, a failing ECM, or issues with the vehicle's electrical system.

How is P220C diagnosed?

Diagnosis typically involves scanning for codes, inspecting wiring and connectors, testing the NOx sensor's voltage supply, and checking for exhaust leaks. Advanced diagnostics may require specialized equipment.

Can I diagnose P220C myself?

While basic checks can be performed, proper diagnosis often requires specialized tools and expertise. It's recommended to have a professional technician diagnose this issue.

How is P220C repaired?

Repairs may involve replacing the faulty NOx sensor, repairing damaged wiring, cleaning corroded connections, or in some cases, replacing the ECM. The specific repair depends on the root cause.

What parts are commonly replaced to fix P220C?

The most commonly replaced part is the NOx sensor itself. Other potential replacements include wiring harnesses, connectors, or in rare cases, the ECM.

How much does it typically cost to repair P220C?

Repair costs can vary widely depending on the cause and required parts. Expect to pay anywhere from $200 to $800 for diagnosis and repair, with NOx sensor replacement being on the higher end.

Can P220C cause damage to my vehicle if left unrepaired?

While not immediately damaging, prolonged operation with P220C can lead to increased emissions, reduced fuel efficiency, and potential damage to the catalytic converter over time.

Is P220C a generic or manufacturer-specific code?

P220C is a generic powertrain code applicable to various manufacturers using OBD-II systems, though specific diagnostic procedures may vary by make and model.

How does the NOx sensor relate to emissions control?

The NOx sensor measures nitrogen oxide levels in the exhaust, providing crucial data for the ECM to adjust engine operation and ensure proper emissions control.

Can a P220C code clear itself?

While the code may occasionally clear if the issue is intermittent, it will likely return if the underlying problem isn't addressed. Proper diagnosis and repair are recommended.

Are there any common misdiagnoses related to P220C?

Sometimes P220C can be misdiagnosed as a faulty sensor when the real issue is with wiring or the ECM. A thorough diagnostic process is crucial to avoid unnecessary parts replacement.

How can I prevent P220C from occurring?

Regular maintenance, including timely replacement of worn components and addressing exhaust leaks promptly, can help prevent P220C. Also, avoid exposure to extreme environmental conditions when possible.

Does P220C affect vehicle performance?

In most cases, P220C primarily affects emissions control. However, in some vehicles, it may lead to reduced engine performance or fuel efficiency as the ECM adjusts engine operation to compensate.

Can aftermarket modifications cause P220C?

Yes, certain aftermarket exhaust modifications or engine tuning can potentially trigger P220C by altering the operating conditions the NOx sensor is designed to measure.

Are there any related codes to P220C?

Related codes include P220B (NOx Sensor Circuit Range/Performance Bank 2 Sensor 1) and P229F (NOx Sensor Circuit Intermittent Bank 2 Sensor 1). These often indicate similar or related issues.

How long does it typically take to repair a P220C issue?

Repair time can vary depending on the cause and required parts. Simple repairs like sensor replacement might take 1-2 hours, while more complex wiring issues could take several hours to diagnose and repair.