P2626 OBD-II Trouble Code: O2 Sensor Pumping Current Trim Circuit/Open Bank 1 Sensor 1

P2626 Code Definition

The P2626 code is a generic powertrain code related to computer circuit output issues. This code appears when the engine control module (ECM) has received a voltage signal from oxygen sensor number 1 pumping current trim circuit for bank 1 that is not within the accepted variances. This typically means the engine block contained the number 1 cylinder is impacted and a fault has been found in the sensor ahead of the catalytic converter (upstream sensor or sensor 1).

The P2626 code is related to:

• P2627 O2 Sensor Pumping Current Trim Circuit Low Bank 1 Sensor 1
• P2628 O2 Sensor Pumping Current Trim Circuit High Bank 1 Sensor 1
• P2629 O2 Sensor Pumping Current Trim Circuit/Open Bank 2 Sensor 1
• P2630 O2 Sensor Pumping Current Trim Circuit Low Bank 2 Sensor 1
• P2631 O2 Sensor Pumping Current Trim Circuit High Bank 2 Sensor 1
• P2195 O2 Sensor Signal Stuck Lean Bank1 Sensor 1
• P2196 O2 Sensor Signal Stuck Rich Bank1 Sensor 1

What the P2626 Code Means

If a P2626 code appears, your vehicle’s ECM has received a voltage signal from oxygen sensor number 1 pumping current trim circuit for bank 1 that is not within the accepted variances. This typically means the engine block contained the number 1 cylinder is impacted and a fault has been found in the sensor ahead of the catalytic converter (upstream sensor or sensor 1). After reaching normal operating temperature and the ECM reaches closed-loop operations, upstream heater oxygen sensor readings should vary consistently from 100 to 900 millivolts.

It could also be due to an oxygen sensor reading being lower than allowed variances. When the voltage signal variance exceeds 10%, either high or low, the ECM will store a P2626 code. The ECM uses the signals from the oxygen sensor to monitor if the air and fuel mixture is too rich or too lean and increases or decreases the fuel injection duration. A damaged sensor can cause the air/fuel mixture to be too rich or too lean for the engine’s needs.

What Causes the P2626 Code?

The P2626 code is caused by a number of possible issues, including:

• Damaged or defective oxygen bank 1 sensor 1
• Damaged, defective, shorted, or open sensor harness
• Damaged or defective oxygen sensor electrical connectors
• Faulty or blown fuse for the oxygen sensor
• Too low or too excessive fuel pressure
• Possible vacuum leak in the engine
• Possible exhaust leak
• Damaged or defective oxygen sensor 1
• Damaged or faulty ECM (rare)

What are the Symptoms of the P2626 Code?

The symptoms of a P2626 code may include:

• Warning or Check Engine Light illuminated
• Possible sputtering or stalling at engine idle
• Vehicle hesitation during acceleration
• Poor fuel efficiency
• Tailpipe may produce black smoke

How Does a Mechanic Diagnose the P2626 Code?

A mechanic may use a variety of methods to diagnose a P2626 code, including:

• Use an OBD-II scanner to check for a stored P2626 code in the ECM
• Perform a visual inspection of all wires and connections
• Check for any damaged or burned wiring harnesses
• Remove the oxygen sensor, if possible and check for signs of damage
• Check the sensor readings through the use of a digital volt or ohmeter
• Test voltages to individual oxygen sensor heater circuits, including both power and ground
• Clear all codes and test drive the vehicle to see if they reappear

Common Mistakes when Diagnosing the P2626 Code

One common mistake when diagnosing the P2626 code is replacement of the incorrect sensor. Additionally, overlooking and not repairing or replacing damaged wires can result in multiple replacements of the oxygen sensor or related parts. Finally, replacing the oxygen sensor when lean or rich air/fuel mixtures are the actual reason for the code.

How Serious is the P2626 Code?

Because a P2626 code stored in your ECM could result in your vehicle stalling or hesitating during acceleration, causing dangerous driving conditions, YourMechanic considers this a potentially serious issue. Take your vehicle into your local dealer service center of repair shop for diagnosis and repair immediately.

What Repairs can Fix the P2626 Code?

• Replace oxygen sensor 1 bank 1
• Replace or repair damaged or defective wiring harnesses
• Replace or repair any damaged wires and electrical connectors
• Replace any faulty or blown fuses for the oxygen sensor
• Too low or too excessive fuel pressure
• Repair or replace any damaged hoses
• Replace or repair a damaged or faulty ECM (rare)

Need Help with a P2626 Code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.