Troubleshooting P0113: Intake Air Temperature Circuit Low Input
START HERE: At the core of your Honda's P0113 IAT Sensor Circuit High Voltage OBD II diagnostic trouble code (DTC) is the fact that the PCM is sensing an intake air temperature of -4°F (-20°C) or colder...
... the cool thing is that you and I can see the actual air temperature the PCM is sensing using a scan tool with Live Data capability (if you don't have a scan tool with Live Data capability and need to buy one, check out my Actron CP9580 Scan Tool Review).
Also, it's possible to test the IAT sensor, before we run out and buy it, to make sure it's really fried. So, to get this show on the road, let me briefly describe the 3 tests you'll be doing to troubleshoot the P0113 IAT Sensor Circuit High Voltage diagnostic trouble code (DTC) lighting up your Honda's check engine light (CEL).
Basically, you will:
- Check what air temp the IAT sensor is reporting.
- This first test is done with a scan tool with Live Data capability.
- What we're looking for is to see if the IAT sensor is reporting a temp that's -4°F (-20°C) or colder.
- TEST 1: Checking The Intake Air Temperature Value.
- Check that the IAT sensor circuits for an ‘open’ short.
- We'll check that the IAT sensor's connector is OK and not damaged (which could be causing a false contact condition).
- This involves removing the hard plastic protector that's over the wires and inspecting the condition of the two IAT sensor wires.
- We'll also do a wiggle test of the IAT sensor's 2 wires.
- TEST 2: Checking The Condition Of The IAT Sensor's 2 Wires.
- Jumpering together the IAT sensor's circuits.
- In this test step, we'll unplug the IAT sensor from its connector and then jumper the two terminals, then via the scan tool's Live Data mode, see if the PCM now reads 300°F (150 °C).
- This test will help you to eliminate a bad PCM and/or a hidden electrical ‘open’ short somewhere in the wiring between the PCM and IAT sensor.
- TEST 3: Jumpering Together the IAT Sensor's Circuits.
TEST 1: Checking The Intake Air Temperature Value
As mentioned before, when your Honda's PCM registers a trouble code P0113 IAT Sensor Circuit High Voltage, it's because the IAT sensor is stuck reporting an air temperature of -4°F (-20°C) or colder.
So in this first test, we'll connect the scan tool and in its Live Data mode, check the actual air temperature your Honda's PCM is seeing and thus confirm the P0113 DTC.
If the PCM is seeing an abnormal temperature, then we can proceed to the other two tests.
IMPORTANT: To ensure the accuracy of this test, your Honda's engine should be completely cold before you start.
OK, this is what you need to do:
Connect your scan tool to your Honda (or Acura) car or mini-van and turn the key to the on position.
NOTE: This test is done with the Key On Engine OFF (KOEO).
Once the scan tool has powered up, go to its Live Data mode.
Scroll down to the PID labeled IAT (°F)
- In case you're wondering what the acronym PID stands for, it's: Parameter Identification.
The scan tool should register a temperature that should be within ±10 °F of ambient temperature (if all is normal)
- So let's say that it's 50 °F outside, then the IAT sensor PID should register something between 40 to 60 °F.
Now, since you're here because you have an IAT sensor diagnostic trouble code (DTC), more than likely you'll see one of the following:
- -4°F (-20°C).
- 300°F (-150°C).
- The current outside air temperaute.
Let's interpret your test results:
CASE 1: Your scan tool shows a -4 °F (-20°C) reading. This confirms DTC P0113 and that you do have a problem with the intake air temperature (IAT) sensor or its circuits.
Seeing an extreme cold temperature of -4 °F (-20°C) indicates one of two things, either that the IAT sensor is bad or the IAT sensor connector's wires have an ‘open’ short (think unplugged sensor).
The next step is to physically check the condition of the wires and do a simple wiggle test. Go to: TEST 2: Checking The Condition Of The IAT Sensor's 2 Wires.
CASE 2: Your scan tool shows a 300 °F reading. This confirms that there is a problem with the intake air temperature (IAT) sensor. You'll also see a diagnostic trouble code P0113 (IAT Sensor Circuit High Voltage) stored in the PCM's memory.
The most likely cause will be that the IAT sensor circuits (wires) are shorted together. This usually happens in the section of the 2 wires nearest to the IAT sensor's connector.
For further testing of this condition, see the following tutorial: P0112 IAT Sensor Circuit Low Voltage (Honda 2.2L, 2.3L).
CASE 3: Your scan tool shows a temperature reading that's ±10 °F of ambient temperature- This tells you that at the moment the IAT sensor and its circuits are OK and more importantly, that the problem is intermittent.
But, since your scan tool retrieved a DTC P0113 the problem may just be hiding at the moment, I recommend clearing the diagnostic trouble code (DTC) and road testing your vehicle to see if the code comes back.
If the P0113 DTC does come back, repeat this test once more.