P2012 – Intake Manifold Runner Control Circuit Low (Bank 2)

What is Code P2012?

P2012 is a generic OBD-II diagnostic trouble code that stands for "Intake Manifold Runner Control Circuit Low (Bank 2)". It indicates an issue with the intake manifold runner control (IMRC) system on bank 2 of the engine.

Urgency of P2012

When code P2012 is triggered, limited driving is generally okay in the short-term. However, the underlying problem should be diagnosed and repaired as soon as possible to prevent further damage. While immediately stopping driving or going to a dealer is not necessary, this issue should not be ignored for an extended period.

Technical Details

The IMRC system uses butterfly valves to adjust the length of the intake runners, optimizing airflow into the engine at different RPMs. The powertrain control module (PCM) controls the IMRC actuators/solenoids.

If the PCM detects low voltage in the IMRC circuit on bank 2, it triggers code P2012. Although this is a generic code applying to all makes, the exact IMRC system configuration varies between manufacturers.

Common Causes

Frequent causes of code P2012 include:

• Faulty IMRC actuator or solenoid
• Damaged wiring/connectors in the IMRC circuit
• Vacuum leaks in IMRC lines
• Faulty PCM (uncommon)

Symptoms

Potential symptoms of code P2012 are:

• Illuminated check engine light
• Reduced engine performance
• Decreased fuel efficiency
• Rough idle or stalling
• Hesitation upon acceleration

Diagnosis Steps

To diagnose code P2012, a mechanic typically:

1. Scans for codes with an OBD-II scanner
2. Visually inspects IMRC actuators, wiring, and vacuum lines
3. Tests voltage and resistance of IMRC actuator circuits
4. Checks for vacuum leaks
5. Inspects IMRC valve plates for damage/binding

Repair Options

Fixes for code P2012 depend on the identified cause:

• Replacing a faulty IMRC actuator/solenoid
• Repairing damaged wiring, connectors, or vacuum lines
• Cleaning dirty/stuck IMRC valve plates
• Replacing the PCM if defective (rare)

Repair Cost

Repairing code P2012 averages $150-600 USD (€135-540 EUR), depending on the exact issue and if parts need replacement. An IMRC actuator alone costs $50-300 USD (€45-270 EUR).

Prevention

To help prevent P2012:

• Change engine oil and air filter regularly
• Periodically inspect vacuum lines for leaks
• Avoid modifications that may impact the IMRC system

Related Codes

Code P2012 may appear with other IMRC system codes like:

• P2008 – Intake Manifold Runner Control Circuit Open (Bank 1)
• P2011 – Intake Manifold Runner Control Circuit Low (Bank 1)
• P2017 – Intake Manifold Runner Position Sensor/Switch Circuit Low (Bank 1)

I hope this detailed article on OBD-II code P2012 is helpful for your website's engineering and mechanic audience. Let me know if you need any other information!

Frequently Asked Questions About P2012

What does the OBD-II code P2012 mean?

P2012 is a generic diagnostic trouble code that stands for "Intake Manifold Runner Control Circuit Low (Bank 2)". It indicates an issue with the intake manifold runner control (IMRC) system on bank 2 of the engine.

How serious is code P2012? Is it safe to keep driving?

Code P2012 itself is not extremely serious and limited driving is generally okay in the short-term. However, the underlying problem should be diagnosed and repaired as soon as possible to prevent potential damage to the engine. Immediately stopping driving or going to a dealer is usually not necessary.

What are the common symptoms of code P2012?

Common symptoms that may be noticed with code P2012 include:

• Check engine light illumination
• Reduced engine performance, especially at low RPMs
• Rough idle or stalling
• Hesitation upon acceleration
• Decreased fuel efficiency

What causes code P2012 to be triggered?

Potential causes of code P2012 are:

• Faulty IMRC actuator or solenoid
• Damaged wiring or connectors in the IMRC circuit
• Vacuum leaks in IMRC vacuum lines
• Carbon buildup on IMRC valve plates
• Faulty PCM (uncommon)

How do you diagnose code P2012?

To properly diagnose the root cause of code P2012, a mechanic will typically:

1. Scan for codes using an OBD-II scanner
2. Visually inspect the IMRC actuators, wiring, and vacuum lines
3. Test the voltage and resistance of the IMRC actuator circuits
4. Check for vacuum leaks using a smoke machine
5. Inspect the IMRC valve plates for damage or binding

What parts need to be replaced to fix code P2012?

Depending on the exact cause identified, parts that may need to be replaced include:

• IMRC actuator or solenoid
• Wiring, connectors, or vacuum lines
• IMRC valve plates (if damaged)
• PCM (rarely)

How much does it cost to repair code P2012?

The average cost to repair code P2012 ranges from $150-600 USD (€135-540 EUR). An IMRC actuator alone costs around $50-300 USD (€45-270 EUR). The total cost depends on the specific issue found and if any parts require replacement.

Can I diagnose and fix code P2012 myself?

Diagnosing and repairing code P2012 requires intermediate mechanical skills and specialty tools like an OBD-II scanner and multimeter. It's not recommended for beginners to attempt alone. If you are experienced with car repairs, you may be able to diagnose and fix it yourself, but most people should take their vehicle to a professional mechanic.

How long does it take to repair code P2012?

The time required to repair code P2012 varies based on the root cause and parts availability. Something simple like replacing a damaged vacuum line may only take an hour, while more complex electrical issues or replacing the IMRC actuator can take several hours. Expect to leave your vehicle at the shop for at least a day in most cases.

Can code P2012 cause damage to my engine if left unrepaired?

Yes, ignoring code P2012 for an extended period can potentially lead to engine damage. If the IMRC system is not working properly, it can negatively affect air-fuel ratios and engine performance. Over time, this added strain on the engine may cause premature wear or more serious problems. It's best to have the issue resolved promptly.

Will code P2012 cause my vehicle to fail an emissions test?

It's possible for code P2012 to cause your vehicle to fail an emissions or smog test, depending on the regulations in your area. Since the IMRC system affects the engine air-fuel mixture, a malfunction can increase tailpipe emissions beyond acceptable limits. The check engine light being on is also usually an automatic failure for emissions testing.

Can a weak battery or charging system cause code P2012?

While less common than other causes, a weak vehicle battery or malfunctioning charging system can potentially trigger code P2012. The IMRC actuators are electrically controlled, so low voltage may disrupt their operation and be interpreted by the PCM as a circuit malfunction. However, there will usually be other signs of electrical issues as well, not just code P2012.

Can aftermarket modifications cause code P2012?

Yes, certain aftermarket modifications can lead to code P2012 setting. Examples include:

• Aftermarket intake or exhaust parts that change airflow
• Modifications to the intake manifold
• Performance chips or tuners that alter engine operating parameters

If you have code P2012 and aftermarket parts installed, the modifications may be responsible.

Can a blown fuse cause code P2012?

Yes, a blown fuse that cuts power to the IMRC actuators or their control circuit can cause code P2012 to set. The PCM will detect the lack of voltage and interpret it as a circuit problem. Checking the relevant fuses is an important step in diagnosing this code. Fuses usually blow due to an overloaded circuit or short.

Can a vacuum leak cause code P2012?

Vacuum leaks are a common cause of code P2012. The IMRC actuators are vacuum-operated, so a leak in the lines that feed them can prevent proper operation. The PCM may detect the lack of expected runner control and trigger the code. Vacuum leaks can occur from cracks in the lines, loose connections, or deteriorated seals.

Can a dirty air filter cause code P2012?

A dirty air filter alone does not typically cause code P2012. The IMRC system operates independently of the main air intake filter. However, a severely restricted filter can affect overall engine airflow and performance. This may contribute to drivability issues in conjunction with IMRC problems. It's still a good idea to check and replace the air filter, but it likely won't resolve code P2012 on its own.

Can low oil level cause code P2012?

No, engine oil level does not directly affect the IMRC system or code P2012. The actuators are electrically and vacuum controlled, not hydraulic. Low oil may cause other engine issues but is unlikely to be the sole cause of this specific code. However, it's always wise to maintain proper oil level for engine health and performance.

Can code P2012 cause overheating?

Code P2012 does not commonly cause engine overheating. The IMRC system affects air intake and fuel mixing, not the cooling system. However, the opposite may be true – an overheating engine might cause problems with the IMRC actuators or their circuit. If you have both code P2012 and overheating, they may be separate issues or the overheating could be the root cause.

Can code P2012 cause a rough idle?

Yes, a rough or unstable idle is a common symptom of code P2012. If the IMRC system is not controlling the intake runners properly, the engine may run poorly at low speeds or RPMs. This can manifest as a rough idle, stalling, or even dying when coming to a stop. The idle may also oscillate or surge.

Can code P2012 affect transmission shifting?

Code P2012 is an engine-related fault and does not directly control transmission shifting. However, because the engine and transmission work closely together, IMRC issues that affect engine performance and RPMs may indirectly impact transmission behavior. Hesitation, surging, or inconsistent power delivery from the engine can make shifts feel unusual. The transmission control module may also alter shift points to try to compensate for engine troubles.