The throttle position sensor in your Mazda is also known as the 626 TPS Sensor. This sensor is a potentiometer that’s mounted inside of your throttle body. When you start your engine and depress your gas pedal, the throttle body opens. The 626 TPS Sensor is a three pin unit that reads the position of your throttle blade, and sends this data to your Mazda computer.
The Mazda engine computer in your 2.0 liter 626 uses this data to properly ramp up the fuel curves as your throttle opens further. When this sensor breaks or there’s a problem with the seating in your 626 TPS Sensor, it’s going to be difficult for your 2.0 liter engine to operate properly.
Today I’ll be showing you how to fix you 626 TPS Sensor in a 2000 Mazda with the 4 cylinder 2.0 liter engine in it. When you’ve got a OBDII trouble code related to your throttle position sensor, you can use this How To tutorial to test the sensor.
When your Mazda 626 check engine light turns on through your instrument cluster, you’ll need an OBDII scan tool to read the code in question.
Symptoms of a bad Mazda 626 TPS Sensor
Because your engine computer won’t have a proper reading from your TPS sensor, most of the issues you’ll see are throttle related. Here’s some of the more common problems when your 626 TPS sensor goes kaput.
- Engine hesitation
- Poor throttle response
- Uncontrollable engine RPM
- Check Engine Light ON
- Bad gas mileage
- Harsh shifting transmission
Have any of these issues plaguing your Mazda? Then this How To guide is for you when you want to test your Mazda throttle position sensor. In order to complete this guide however, you’ll need a digital multimeter.
If you own a 1994 Mazda 626 with the 2.0 liter engine, your check engine code will be an OBDI variety. There’s three codes that are available from your OBDI Mazda in relation to your TPS sensor.
OBDI Code 121: TPS and MAF Signal mismatch
OBDI Code 122: TPS Voltage Too Low
OBDI Code 123: TPS Voltage Too High
If your 626 is a 1996 model or above you’ll be able to connect to the OBDII port to retrieve the engine code.
How To Test a Mazda 626 TPS Sensor
The first part of our guide is to locate your throttle sensor. It’s mounted towards the rear of the engine bay, connected to your throttle body in your 2.0 liter engine.
Once you’ve found this sensor unplug it to test for power and ground signals. Insert your Mazda ignition key and turn to the “ON” position and at that point you are ready.
Testing the 626 TPS Sensor for Power
The wire that leads to PIN C is the power wire for your 626 TPS sensor. This wire is a BLACK one with a YELLOW stripe, and using your multimeter you should see around 5 volts of power here.
The next wire you are checking is PIN A which is the low reference ground wire. This is a GRAY wire with a RED stripe in it. Once you’ve determined power and ground are good, it’s time to move onto testing your 626 TPS sensor signal wire.
Testing the 626 TPS Sensor for Signal
Now reconnect your Mazda throttle position sensor. The wire you will need to measure or pierce with your multimeter lead is PIN B or the PURPLE wire with a YELLOW stripe in it. Leave your engine off but the key turned to the “ON” position.
With your throttle plate closed you should see between .2 and .9 volts of DC signal at this wire. Now slowly push open your throttle body by hand and measure the voltage at Wide Open Throttle or 100% open. At this throttle blade position, your 626 TPS sensor signal should read between 4.1 and 4.8 volts of DC signal.
If your Mazda throttle sensor does not respond with these values, bad news it’s time for a replacement sensor. You can replace the TPS sensor without replacing the throttle body, although you’ll need to calibrate it correctly for proper use with a multimeter.
Have any questions about this 626 TPS Sensor DIY tutorial? Leave us a comment below and let us know!