P0122 TPS Code Explained (2002-2007 4.7L V8 Dodge Ram Pickup)

  • By: Abraham Torres-Arredondo
  • Created: 01 July 2025
  • Updated: 01 July 2025
  • Articl Id: 844
P0122 TPS Code Explained (2002, 2003, 2004, 2005, 2006, 2007 4.7L V8 Dodge Ram Pickup)

When your 2002–2007 4.7L V8 Dodge Ram pickup sets a P0122 trouble code, it means the throttle position sensor (TPS) is reporting a voltage that's too low for the current throttle angle.

This can cause poor throttle response, hesitation when accelerating, and may even throw the engine into reduced power mode.

In most cases, this code is caused by a bad TPS sensor or a problem with its signal or 5 Volt reference circuit.

In this guide, I'll show you what code P0122 really means, what causes it, and how to fix it without guessing or replacing good parts.

Contents of this tutorial:

APPLIES TO: This tutorial applies to the following vehicles:

  • 4.7L V8 Dodge Ram 1500 Pickup: 2002, 2003, 2004, 2005, 2006, 2007.

TPS MULTIMETER TESTS:

TPS WIRING DIAGRAMS:

OTHER TPS TROUBLE CODES EXPLAINED:

What Does P0122 Really Mean?

DTC code definition, depending on what your scan tool displays:

  • Generic Definition: P0122 – Throttle/Pedal Position Sensor/Switch A Circuit Low Input.
  • Factory Definition: P0122 – Throttle Position Sensor Voltage Low.

This trouble code gives us a big clue —not just that something's wrong with the TPS, but how it's failing (or why the PCM "thinks" it's bad). That clue is gold when you're diagnosing and troubleshooting the issue.

Put simply, code P0122 means the PCM is seeing a throttle position sensor (TPS) voltage that's too low —typically below 0.2 Volts— even though the throttle isn't completely closed.

On your 2002–2007 4.7L V8 Dodge Ram pickup, the TPS normally outputs a voltage between about 0.3 and 4.5 Volts —depending on throttle angle (which, as you know, changes based on how much you press or let off the gas pedal).

If the voltage drops below 0.16 Volts for more than about 0.7 seconds, the PCM considers the signal invalid and sets the P0122 TPS voltage low code.

This kind of low or stuck signal can confuse the PCM and cause poor throttle response, sluggish acceleration, or erratic engine performance (but more about these in the next section).

Common Symptoms Of Code P0122

When your Dodge Ram throws a P0122 TPS voltage low code, it usually comes with some noticeable driveability problems.

Here's what you might experience on a 2002–2007 4.7L V8 Dodge Ram pickup with a P0122 code:

  • Sluggish or delayed throttle response.
  • Engine hesitation when you try to accelerate.
  • Rough idle or stalling when coming to a stop.
  • Transmission may shift hard or late.
  • Reduced engine power.

These symptoms can come and go —mainly if the TPS is starting to fail intermittently or if the signal wire has a poor connection. I'll go deeper into this in the next section.

What Causes Code P0122?

As we previously discussed, code P0122 is set when the PCM detects a throttle position sensor (TPS) voltage that's lower than expected.

For the most part, this is usually caused by the sensor itself being bad, but not always. There are a few possible reasons this code shows up on your 2002–2007 4.7L V8 Dodge Ram pickup:

  • A worn-out or failing TPS sensor (one that hasn't kicked the bucket completely yet).
  • The sensor has a problem getting 5 Volts from the PCM.
  • A broken or shorted TPS signal wire.
  • Corroded or loose TPS connector terminals.
  • PCM internal fault (rare).

The only way to know for sure is to test the TPS with a multimeter. You can check the TPS signal, verify the 5 Volt reference, and confirm the Ground circuit —all with just a multimeter.

If you're ready to dive in, here's a full step-by-step guide that walks you through the process:

In the next section, I'll help you decide whether testing or replacing the TPS makes more sense for your situation.

Should You Replace The TPS?

Up to this point, we've covered how a P0122 TPS voltage low code on your 2002–2007 4.7L V8 Dodge Ram pickup could be caused by a bad throttle position sensor —but it could just as easily be a wiring issue, or a missing 5 Volt or Ground supply.

So the big question is: should you test the TPS first or just replace it? Let's walk through it together.

Most folks (and even some shops) skip testing and just replace the sensor. And I'll be honest —eight times out of ten, that solved the problem. The part isn't expensive, it's easy to get to, and swapping it out often gets the truck back on the road without much hassle.

If you're leaning that way, here are a couple of TPS replacement options that fit the 2002–2007 4.7L V8 Dodge Ram pickup. These are trusted parts from known brands —and purchasing through these links helps support this site without costing you anything extra:

That said, I want to point out the two main reasons it's a good idea to test it:

  • Sometimes the TPS isn't the actual problem. If it's not getting power, Ground, or there's an issue with the connector, replacing it won't fix the root cause.
  • Another very good reason to test it is that the TPS is so easy to test. It's in a very accessible spot, and you don't need a scan tool or special equipment.

All it takes is a basic multimeter and a few minutes to check the signal, power, and Ground. That way, you'll know exactly what's going on —before spending money on a replacement.

Here's my step-by-step guide to checking the TPS signal, power, and Ground using a simple multimeter:

More 4.7L V8 Dodge Ram Pickup Diagnostic Tutorials

I've written quite a few tutorials for the 4.7L V8 Dodge Ram pickup. You can find them in this index:

Here's a small sample of the tutorials you'll find in the index:

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