Symptoms

and severity

The severity is generally serious due to its impact on the cooling system. Since it is typically an electrical failure, the PCM cannot fully compensate for it. Partial compensation usually means the cooling fans run all the time (100% duty cycle).

Symptoms of a P261D code may include:

• Malfunction indicator light on
• Overheating
• Air conditioning system not working properly

Causes

Potential causes for this code being set are as follows:

• Open in the coolant pump circuit – likely
• Coolant pump failure – likely
• PCM failure – unlikely

Diagnostic and Repair Procedures

A good starting point is always to check the Technical Service Bulletins (TSBs) for your specific vehicle. Your issue might be a known problem with a known fix published by the manufacturer and could save you time and money during diagnosis.

Next, locate the B coolant pump (CP-B) on your specific vehicle. This pump is typically found mounted at the front of the engine, on top of the engine, inside the wheel wells, or against the firewall. Once located, visually inspect the connector and wiring. Look for scratches, rubbing, bare wires, burns, or melted plastic. Disconnect the connector and carefully inspect the terminals (the metal parts) inside the connector. Check if they appear burnt or have a greenish tint indicating corrosion. Use electrical contact cleaner and a plastic-bristled brush if cleaning the terminals is necessary. Let it dry and apply electrical grease where the terminals make contact.

If you have a scan tool, clear the diagnostic codes from memory and see if the P261D code returns. If it does not, the connections were likely your problem.

For this particular code, this is the most common area of concern, along with relays/connections to relays, with pump failure being the second most common.

If the code returns, we will need to test the pump and related circuits. Typically, there are 2 wires for each coolant pump. First, disconnect the harness going to the coolant pump. With a digital volt ohm meter (DVOM), connect one meter lead to one terminal of the pump. Connect the remaining meter lead to the other pump terminal. It should not be open or shorted. Check the resistance specifications for your specific vehicle. If the pump motor is open or shorted (infinite resistance or no resistance/0 ohms), replace the coolant pump.

If this test passes, with a DVOM, check that you have 12V at the coolant pump power circuit (red lead to the pump power circuit, black lead to a good ground). With a scan tool that can activate the coolant pump, turn on the coolant pump. If there is no 12 volts at the pump, repair the wiring from the PCM or relay to the pump, or possibly a faulty PCM.

If that checks out, verify the coolant pump ground circuit. Connect a test light to the positive 12V battery terminal (red terminal) and touch the other end of the test light to the ground circuit going to the coolant pump circuit ground. Using the scan tool to actuate the coolant pump, check if the test light illuminates each time the scan tool actuates the pump. If the test light does not illuminate, it would indicate a problem with the ground circuit. If it does light up, wiggle the wiring harness going to the pump to see if the test light flickers, indicating an intermittent connection.

If all previous tests have passed and you continue to get a P261D, it would most likely indicate a failing coolant pump, although a faulty PCM cannot be ruled out until the coolant pump has been replaced. If in doubt, seek assistance from a qualified automotive diagnostician. PCMs need to be programmed or calibrated to the vehicle to be installed correctly.

Other similar coolant pump codes include P2600, P2601, P2602, and P2603.

P2620 Possible Causes

• Faulty throttle position sensor/switch
• Throttle position sensor/switch harness is open or shorted
• Poor electrical connection in throttle position sensor/switch circuit

How to Fix Code P2620

Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Look for damaged components and check for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Illuminated engine light (or service engine soon warning light)

P2620 Meaning

The Engine Control Module (ECM) monitors the throttle position circuit signal. The ECM sets the OBDII code when the throttle position circuit signal is outside factory specifications.

P2621 Possible Causes

• Faulty throttle position sensor/switch
• Throttle position sensor/switch harness is open or shorted
• Poor electrical connection in throttle position sensor/switch circuit

How to Fix Code P2621

Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Illuminated engine light (or service engine soon warning light)

P2621 Meaning

The Engine Control Module (ECM) monitors the throttle position circuit signal. The ECM sets the OBDII code when the throttle position circuit signal is outside factory specifications.

P2622 Possible Causes

• Faulty throttle position sensor/switch
• Throttle position sensor/switch harness is open or shorted
• Poor electrical connection in throttle position sensor/switch circuit

How to Fix Code P2622

Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Illuminated engine light (or service engine soon warning light)

P2622 Meaning

The Engine Control Module (ECM) monitors the throttle position circuit signal. The ECM sets the OBDII code when the throttle position circuit signal is outside factory specifications.

P2623 Possible Causes

• Faulty injector control pressure regulator
• Injector control pressure regulator harness is open or shorted
• Poor electrical connection in injector control pressure regulator circuit

How to Fix Code P2623

Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Illuminated engine light (or service engine soon warning light)

P2623 Meaning

The Powertrain Control Module (PCM) monitors the Injector Control Pressure Regulator (ICPR) circuit. The PCM sets the OBDII code when the injector control pressure regulator circuit is outside factory specifications.

P2624 Possible Causes

• Faulty injector control pressure regulator
• Injector control pressure regulator harness is open or shorted
• Poor electrical connection in injector control pressure regulator circuit

How to Fix Code P2624

Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

Possible Symptoms

Illuminated engine light (or service engine soon warning light)

P2624 Meaning

The Powertrain Control Module (PCM) monitors the Injector Control Pressure Regulator (ICPR) circuit. The PCM sets the OBDII code when the injector control pressure regulator circuit is outside factory specifications.

🔧 Code P2625 – Injector Control Pressure Regulator

📌 Meaning of Code P2625

The Powertrain Control Module (PCM) monitors the Injector Control Pressure Regulator (ICPR) circuit. Code P2625 is stored when this circuit operates outside factory specifications.

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🚨 Possible Symptoms

• Check Engine light (or “Service Engine Soon” warning light)

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❗ Possible Causes

• Faulty injector control pressure regulator
• Injector control pressure regulator wiring open or shorted
• Poor electrical connection in the injector control pressure regulator circuit

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🛠️ How to Fix Code P2625

1. Check the possible causes mentioned above.
2. Visually inspect the wiring harness and associated connectors.
3. Look for:
   • Damaged components
   • Broken, bent, pushed out, or corroded connector pins

Code Severity and Symptoms

The severity of this code is moderate but will progress if not corrected in a timely manner. Symptoms of a P2628 fault code may include:

• Worsening poor performance
• Engine running lean
• Engine running rich
• Check engine light illuminated
• Smoke from the exhaust pipe
• Increased fuel consumption

Common Causes of P2628 Code

Possible causes of this code may include:

• Faulty O2 sensor
• Carbon buildup on the O2 sensor
• Blown fuse (if applicable)
• Fuel pressure too high
• Fuel pressure too low
• Engine vacuum leak
• Excessive exhaust leak
• Corroded or damaged connector
• Faulty or damaged wiring
• Faulty PCM

Common Repairs

• Replacement or cleaning of the O2 sensor
• Replacement of blown fuse (if applicable)
• Adjusting fuel pressure
• Repairing engine vacuum leaks
• Repairing exhaust leaks
• Cleaning connector corrosion
• Repairing or replacing wiring
• PCM replacement

P2628 Diagnostic and Repair Procedures

Check TSBs
The first step in troubleshooting any malfunction is to search for Technical Service Bulletins (TSBs) for the specific vehicle by year, model, and powertrain. In some circumstances, this can save significant time in the long run by pointing you in the right direction.

The second step is to locate the pre-catalytic converter O2 sensor. Perform a thorough visual inspection to check the associated wiring for obvious defects such as scraping, rubbing, bare wires, or burns. Then, check the connector for security, corrosion, and damaged pins. With the engine running, the visual inspection should include identifying possible exhaust leaks. Based on fuel consumption and fuel pressure tests, engine operation adjustments may be recommended. You should consult specific technical data to determine this requirement.

Advanced Steps

Advanced steps become very vehicle-specific and require appropriate advanced equipment to perform accurately. These procedures require a digital multimeter and vehicle-specific technical references. Voltage requirements will be highly dependent on the specific vehicle year, model, and engine.

Voltage Checks

When the fuel mixture is balanced at approximately 14.7:1, which is normal for most engines to achieve optimal performance, the sensor will read about 0.45 volts. An oxygen sensor typically generates up to about 0.9 volts when the fuel mixture is rich and there is unburned oxygen in the exhaust gases. When the mixture is lean, the sensor’s output voltage will drop to about 0.1 volts.

If this process identifies the absence of a power source or ground, continuity tests may be required to check wiring integrity. Continuity tests should always be performed with the power disconnected from the circuit, and normal readings should be 0 ohms of resistance unless otherwise indicated by technical data. Resistance or lack of continuity indicates faulty open or shorted wiring and should be repaired or replaced.

I hope the information in this article has helped point you in the right direction to correct the issue with your O2 sensor pump current compensation circuit. This article is strictly informational, and specific technical data and service bulletins for your vehicle should always take priority.

Code Severity and Symptoms

The severity of this code is moderate but will progress if not corrected in a timely manner. Symptoms of a P2627 fault code may include:

• Worsening poor performance
• Engine running lean
• Engine running rich
• Check engine light illuminated
• Smoke from the exhaust pipe
• Increased fuel consumption

Common Causes of P2627 Code

Causes

Possible causes of this code may include:

• Faulty O2 sensor
• Carbon buildup on the O2 sensor
• Blown fuse (if applicable)
• Fuel pressure too high
• Fuel pressure too low
• Engine vacuum leak
• Excessive exhaust leak
• Corroded or damaged connector
• Faulty or damaged wiring
• Faulty PCM

Common Repairs

• Replacement or cleaning of the O2 sensor
• Replacement of blown fuse (if applicable)
• Adjustment of fuel pressure
• Repairing engine vacuum leaks
• Repairing exhaust leaks
• Cleaning connector corrosion
• Repairing or replacing wiring
• PCM replacement

P2627 Diagnostic and Repair Procedures

Check TSBs
The first step in troubleshooting any malfunction is to search for Technical Service Bulletins (TSBs) for the specific vehicle by year, model, and powertrain. In some circumstances, this can save significant time in the long run by pointing you in the right direction.

The second step is to locate the pre-catalytic converter O2 sensor. Perform a thorough visual inspection to check the associated wiring for obvious defects such as scraping, rubbing, bare wires, or burns. Then, check the connector for security, corrosion, and damaged pins. With the engine running, the visual inspection should include identifying possible exhaust leaks. Based on fuel consumption and fuel pressure tests, engine operation adjustments may be recommended. You should consult specific technical data to determine this requirement.

Advanced Steps

Advanced steps become very vehicle-specific and require appropriate advanced equipment to perform accurately. These procedures require a digital multimeter and vehicle-specific technical references. Voltage requirements will be highly dependent on the specific vehicle’s year, model, and engine.

Voltage Checks

When the fuel mixture is balanced at approximately 14.7 to 1, which is normal for most engines to achieve optimal performance, the sensor will read about 0.45 volts. An oxygen sensor typically generates up to about 0.9 volts when the fuel mixture is rich and there is unburned oxygen in the exhaust gases. When the mixture is lean, the sensor’s output voltage will drop to about 0.1 volts.

If this process identifies the absence of a power source or ground, continuity tests may be required to check wiring integrity. Continuity tests should always be performed with the power disconnected from the circuit, and normal readings should be 0 ohms of resistance unless otherwise indicated by technical data. Resistance or lack of continuity indicates faulty open or shorted wiring and should be repaired or replaced.

I hope the information in this article has helped point you in the right direction to correct the issue with your O2 sensor pump current compensation circuit. This article is strictly informational, and specific technical data and service bulletins for your vehicle should always take priority.

Code Severity and Symptoms

The severity of this code is moderate but will progress if not corrected in a timely manner. Symptoms of a P2626 fault code may include:

• Worsening poor performance
• Engine running lean
• Engine running rich
• Engine light illuminated
• Smoke from the exhaust pipe
• Increased fuel consumption

Common Causes of a P2626 Code

Possible causes of this code may include:

• Faulty O2 sensor
• Carbon buildup on the O2 sensor
• Blown fuse (if applicable)
• Fuel pressure too high
• Fuel pressure too low
• Engine vacuum leak
• Excessive exhaust leak
• Corroded or damaged connector
• Faulty or damaged wiring
• Faulty PCM

Common Repairs

• Replacement or cleaning of the O2 sensor
• Replacement of blown fuse (if applicable)
• Adjusting fuel pressure
• Repairing engine vacuum leaks
• Repairing exhaust leaks
• Cleaning connector corrosion
• Repairing or replacing wiring
• PCM replacement

P2626 Diagnostic and Repair Procedures

Check TSBs
The first step in troubleshooting any malfunction is to search for Technical Service Bulletins (TSBs) for the specific vehicle by year, model, and powertrain. In some circumstances, this can save significant time in the long run by pointing you in the right direction.

The second step is to locate the pre-catalytic converter O2 sensor. Perform a thorough visual inspection to check the associated wiring for obvious defects such as scraping, rubbing, bare wires, or burns. Then, check the connector for security, corrosion, and damaged pins. With the engine running, the visual inspection should include identifying possible exhaust leaks. Based on fuel consumption and fuel pressure tests, engine operation adjustments may be recommended. You should consult specific technical data to determine this requirement.

Advanced Steps

Advanced steps become very vehicle-specific and require appropriate advanced equipment to perform accurately. These procedures require a digital multimeter and vehicle-specific technical references. Voltage requirements will be highly dependent on the specific vehicle year, model, and engine.

Voltage Checks

When the fuel mixture is balanced at approximately 14.7 to 1, which is normal for most engines to achieve optimal performance, the sensor will read about 0.45 volts. An oxygen sensor typically generates up to about 0.9 volts when the fuel mixture is rich and there is unburned oxygen in the exhaust gases. When the mixture is lean, the sensor’s output voltage will drop to about 0.1 volt.

If this process identifies the absence of a power source or ground, continuity tests may be required to check wiring integrity. Continuity tests should always be performed with the power disconnected from the circuit, and normal readings should be 0 ohms of resistance, unless otherwise indicated by technical data. Resistance or lack of continuity is an indication of faulty open or short-circuited wiring and should be repaired or replaced.

I hope the information in this article has helped point you in the right direction to correct the issue with your O2 sensor pump current compensation circuit. This article is strictly informational, and specific technical data and service bulletins for your vehicle should always take priority.