The P0122 Honda OBDII Diagnostic Trouble Code (DTC) refers to the throttle position sensor in your 2.2 or 2.3L Honda. The engine code for this specific model Honda should be F22 or F23, and is usually found in Honda Accords.

Today I’ll be showing you how to test the throttle position sensor (TPS) in your 1998-2001 Honda Accord.

The specific verbiage for this OBDII check engine light is P0122 Honda Throttle Position Sensor Circuit Low Voltage, meaning your ECU is expecting a higher range of voltage from your TPS. This code can cause sluggish behavior and cause your vehicle to buck and stall.

To address this problem, you will need a Phillips screwdriver and a voltmeter of your choice to test the three pin TPS connector on your F22 or F23. If you want to smog your Honda, you’ll need to clear the P0122 Honda code first.

Before we start testing your Honda Accord Throttle position sensor, let’s break down what the TPS is and why your vehicle needs it.

What is the Throttle Position Sensor?

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The Throttle Position Sensor, or TPS is directly responsible for relaying real time data to your ECU so that it knows how much your throttle blade is opening. Using this parameter, as well as a few others the ECU can base it’s fuel and ignition parameters and operate your engine efficiently.

When you depress your gas pedal, this opens your throttle body blade further open, allowing more air to enter your engine. The ratio in which the throttle blade opens is translated by the ECU, which then knows to inject more fuel to compensate.

However, problems can arise when your ECU sees a value that it’s uncomfortable with or isn’t expecting. Because it no longer knows how far open or closed your throttle plate is, bucking or poor fuel economy and driving conditions can occur.

When the expected voltage from the TPS is lower than what Honda originally programmed, is when the OBDII DTC code P0122 TP Sensor Circuit Low Voltage will trigger the check engine light (CEL) on your Honda’s instrument cluster.

How Does the TPS work?

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The TPS sensor is mounted to the throttle body and measures the angle of your throttle body blade. This angle becomes greater as you push down on the accelerator pedal. Voltage is read by the ECU in percentage, with 100% representing Wide Open Throttle (WOT).

When there’s a problem with your Accord throttle position sensor, the P0122 Honda trouble code is extremely common.

How To Test Honda Accord 2.2L TPS

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Lets begin our How To Test tutorial by opening your hood and locating your throttle body. The intake snorkel that leads to your throttle body must be removed to service your throttle position sensor, which is close to your firewall. As space is limited, you must remove the intake snorkel and a few connectors to gain as much room as possible.

The blue connector shown is the three pin Throttle Position Sensor, or TPS connector. To reach this unit however and be able to test with any kind of accuracy, you will need to remove some parts, I will show you what to do now.

First we’ll be moving the vacuum hoses and metal tubes out of the guides located in the intake snorkel. Push these hoses up and out of their grooves so that removing the intake snorkel is easier.

Once you have this tube pushed out, you can now move onto the crankcase vent tube, which can be easily pushed out of the orifice in the intake snorkel.

Next you’ll want to unplug the MAP sensor, and let the three pin MAP sensor connector dangle. Remember in order to fix the P0122 Honda trouble code, you’ll need power at the wiring so keep your ignition key to the ON position, not START.

You are going to need to remove the middle intake snorkel on your 2.2 or 2.3L F22 or F23 to continue to the TPS connector. Unscrew the worm clamp that holds the intake snorkel to the throttle body opening and slide the intake hose off.

Once this intake tube is taken off your F series motor, you should now have enough room to unplug and test the throttle position sensor itself.

Unplug the blue TPS connector and take a look at the orientation of all three wires and what they signify for your Honda Accord. Once you clear a P0122 Honda trouble code, your check engine light should switch off.

Checking for Throttle Position Sensor Power

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Pin 1 on your blue throttle position sensor is for switched 5 volt power, this wire is yellow or yellow with red stripe. Using your voltmeter or similar voltage reading device, turn the key to the “ON” position and backprobe PIN 1. If you see power here, move onto the next section Checking for Throttle Position Ground. If you do not see power here, run a seperate wire from your A24 ECU pin for sensor power to this PIN 1.

Checking for Throttle Position Sensor Ground

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Pin 3 on the TPS connector is a green wire with black stripe, and this should be the sensor ground for your TPS sensor. If you do not see a ground signal here, try grounding it to the chassis temporarily to see if this corrects your DTC P01222.

Testing the Throttle Position Sensor Signal

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Lastly the wire you’ll be testing is the middle wire on your blue throttle position sensor connector. This is the signal wire for your TPS and if you have power and ground at the TPS already, chances are this is the culprit. Backprobe the middle red wire with black stripe with the key set to the “ON” position. Now keeping your voltmeter to the middle wire, push down on the throttle blade to see how much voltage is being sent to the ECU.

Remember to backprobe this middle wire while opening and closing your throttle plate, you should see a smooth sweeping range of voltage, from .5 to 4.5 at wide open throttle. Take your time here to properly troubleshoot and locate the cause of your P0122 Honda trouble code.

If your TPS sensor is not giving the proper range of voltage for operation, it’s time to replace your Honda Accord Throttle Position sensor. Unfortunately, this throttle position sensor is not sold separately from Honda, as they want you to replace the entire throttle body assembly.

If you are comfortable installing a new throttle position sensor, aftermarket units are available but will require you to properly install it on your Honda Accord.

With your TPS replaced, your DTC P0122 Honda trouble code should now be resolved.

Have any questions or problems with our article? Leave us your questions below!