Error Code P0125: What It Means & What To Do?

<<See All OBD Codes

Inadequate engine heat-up time, a coolant temperature sensor defect, a low engine coolant condition, or a thermostat error could cause this.

ECT sensor readings that happen after the OBD-II system has been sent into closed loop operation, and are lower than the manufacturer’s defined value, will cause a trouble code to be stored and a malfunction indicator lamp to be illuminated.

What causes this problem with the Throttle Position Sensor/Switch A Circuit?

• Low Level Engine Coolant
• Thermostat Stuck Open or Leaking
• Defective Engine Coolant Temperature (ECT) sensor
• Engine Coolant Temperature (ECT) sensor harness is shorted or open
• Engine Coolant Temperature (ECT) sensor electrical circuit in bad connection

1. Boost pressure sensor - If the boost pressure sensor fails, you will see a decline of boost power and reduction of engine efficiency. If your boost pressure sensor is damaged, it’s recommended you replace it to prevent your turbocharged car from losing its quality of power and excellence.
2. Turbocharger ­- The turbocharger may be defective for reasons as to low oil levels, to which excess much heat and friction will eventually founder the bearings that are inside. This means you should replace the turbocharger or use internal lubricants to ensure the parts are moving fast and efficiently.
3. Supercharger - A supercharger can start failing for a whole range of reasons, for example a poor level of supercharger oil, broken pulley, and overheating or defective seals/gaskets. If your car's supercharger is not performing accurately, it recommended you replace it instantly.
4. Knock sensor - When detecting a knock sensor, be sure there are no damaged terminal or no corroded wires and connections. A defective knock sensor decreases your car’s functioning excellence, effects the fuel economy and results in costly damage to your engine, so it’s crucial to get the correct knock sensor for your type of car model.
5. Spark Plug - A defective spark plug may occur when acceleration is slow, power is at loss, fuel economy is poor, engine misfires, and the car has difficulty starting. As a result, it is highly considered to replace your spark plug every 30 months or 30,000 miles your car is traveling.
6. Intake manifold - A leaking intake manifold can have destructive effects on your car's engine, resulting in the manifold to take in extra air from outside through the leak source, causing more air to access intake ports and disrupt with the air-fuel relations in the cylinders. It’s recommended to replace the failing manifold as soon as possible to prevent the car's engine from any further damage.
7. Boost Pressure Gauge - If the boost pressure sensor is failing, you will see a decrease of boost power and declined efficiency in your engine. If there is damage to your boost pressure sensor, you should replace it to prevent your turbocharged car from losing its effectiveness.
8. Powertrain Control Module - A defective PCM may cause your car to fail in starting or may begin stalling when running. Inclusively, low emissions may happen due to the failure in controlling the emissions system, so if your PCM is not performing correctly, you need to replace it as soon as possible.
9. Engine Control Module - Your vehicle may have trouble starting even after ensuring the battery and starter are working accurately. If your car's errors wind down to a defective engine control module, you should replace it immediately to prevent further intensive risks to your car.
10. Wastegate - If too much exhaust gas is passed through the turbine, the unit can over accelerate, inducing mechanical stress on it and can result in all sorts of problems, for example breaking of shafts, failed compressor wheels, or a torrent to the engine's internals and power delivery. It’s ethical to adjust the turbo itself and replace an upscale version with one customized for the job.

The TPS engages in an important part of engine drivability, thereby a stored code P0125 should be called forward at a level of swift action. Symptoms of a P0125 code may include:

Common Symptoms

• The Check Engine Light displayed on the instrument panel/dash
• Poor fuel economy
• Overheated car
• Deficient heater performance
• Engine damage

The OBD Code P0125 problems can be fixed with some of these common solutions for your particular car engine:

• If having a scan tool to access, see what functionality the idle and WOT (wide open throttle) readings bring for the TPS. Detect if they're close to the identifications brought up from above. If not the case, then exchange the TPS and re-examine.
• Detect for an irregular open or short voltage within the TPS signal. To achieve this, you should not use a scan tool. What you'll need is an oscilloscope. The reason this occurs is because scan tools take up samples of many different readings just over one or two data lines and can miss an irregular drop out. It is best to hook up the oscilloscope and watch for the signal. It should brush up and down nicely without dropouts or spikes.
• If you don’t notice problems, then carry out a wiggle test. You can achieve this by wiggling the connector and harness as you watch the pattern. Does it successfully drop out? If does so, exchange TPS and re-detect.
• If you don’t have a TPS signal, then check at the connector for 5 Volt references. If presently in view, detect the ground circuit for open or shorts.
• Ensure that the signal circuit is not 12V. It shouldn’t ever have battery voltage. If so, trace the circuit for short to voltage and fix.7
• Check for any water within the connector and replace TPS as needed.

It’s beneficial to always check for technical service bulletins (TSB) in advance for your specific car. You may have a known issue with your engine that has a known fix easily sought by the manufacturer that can save you time and money during this diagnosis. It is common to use a diagnostic scanner, a digital volt/ohmmeter (DVOM) and a precise car information source (ALL DATA DIY) to diagnose a code P0125.

• To start with, check to ensure that the engine is contained with enough suitable coolant so that the thermostat is performing accurately
• Start your diagnosis by watchfully checking for all wiring and connectors
• View for wiring that is shorted or burned and exchange circuitry and connectors as needed
• Suppose if the system wiring, connectors, and components look to be working in normal order, connect the scanner to the diagnostic connector and record all retained trouble codes and freeze frame data
• This data can be immensely helpful in diagnosing irregular conditions that could have provided to this code being retained
• After clearing the codes, run the car to see if the code comes back
• If the code fails to return instantly, you might have an irregular condition
• Irregular conditions can uphold as being such a challenge to diagnose and in intense cases may need be enabled to worsen before precise diagnosis is able be made. Detect the fan clutch (if equipped)
• This code is often set because the driver does not enable adequate engine heat up time (especially in cold weather)
• It is a good idea to reset the code and see if it comes back when this code is on display.

Common Mistakes When Diagnosing The P0125 Code

• Faulty Engine Thermostat
• Faulty Engine Coolant Temperature Sensor
• Faulty Intake Air Temperature Sensor
• Faulty Cooling System
• Poor Engine Coolant
• Filthy Engine Coolant, leading inaccurate Coolant Temperature Sensor scanning
• Faulty Engine Cooling fan(s) that are always running

P0126 - Insufficient Coolant Temperature for Stable Operation