P1100Manufacturer-specific code

P1100 Code: Barometric Pressure Sensor Circuit (Toyota)

On Toyota and Lexus, the P1100 code points to the barometric pressure (BARO) sensor circuit. The fuel mixture is corrected less accurately at altitude. On other brands the same number means something else.

Severity
Low
Can I keep driving?
Yes, no immediate risk
Estimated cost
$0 to $600
Difficulty
Medium
System
Air and Fuel
Applies to
Depends on the manufacturer

Common in: Ford, Toyota

Updated Reviewed by Renzo Chacca

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What the P1100 code means

P1100 is a manufacturer-specific code: the 1 in the second position means each automaker defines what it stands for, not the generic standard. That is why the same number means different things depending on the vehicle, as the table below shows. This page covers the Toyota and Lexus meaning.

ManufacturerMeaning of P1100
Toyota and LexusBarometric pressure (BARO) sensor circuit
Ford, Lincoln and MercuryMass air flow (MAF) sensor intermittent

Some Toyotas measure atmospheric pressure with a sensor built into the computer or located in the engine compartment, so the fuel mixture can be adjusted for altitude.

The computer sets the P1100 code when the barometric sensor signal is out of range. If the sensor is built into the computer, rule out its power supply and grounds first.

Before you repair anything, confirm the make, model, year and engine. With manufacturer codes, the same number can change even between engines from the same brand.

P1100 code symptoms

  • Check engine light on.
  • Slightly less power at high altitude.
  • Usually no noticeable symptoms.

Likely causes of the P1100 code

  1. Barometric sensor or the internal circuit of the computer.
  2. Computer power supply or ground. Uncommon, so rule out everything else first.
  3. Connector. Check the locking tab and the pins, and look for moisture or corrosion.

How to diagnose the P1100 code step by step

  1. Compare the scan tool reading with the real air pressure. It should be about 100 kPa (14.5 psi) at sea level.
  2. Check the power supply and grounds of the computer.
  3. Find out whether the sensor is built in. Look it up in the service manual for your model.

How to fix the P1100 code

  • Repair the power supply or the grounds.
  • Replace the sensor, or the computer if the sensor is built into it.
  • Clear the P1100 code and verify that it does not return.

Technical reference data

  • At sea level: about 100 kPa (14.5 psi). At 2,500 m (about 8,200 ft): about 75 kPa (10.9 psi).
  • P1xxx codes are manufacturer-specific: confirm the definition with a scan tool that supports your brand.
  • Values are approximate: check the manufacturer data for your vehicle.

Brand-specific notes

This code shows up mostly on Toyotas from the 1990s and early 2000s.

If your vehicle is another brand, check the table above for the meaning its manufacturer gives the code, and confirm it with a scan tool that supports that brand.

Frequently asked questions about P1100

What does the P1100 code mean on a Toyota?
It points to the barometric pressure (BARO) sensor circuit. The fuel mixture is corrected less accurately at altitude.
Does P1100 mean the same thing on every brand?
No. On Ford, Lincoln and Mercury it stands for a mass air flow (MAF) sensor that works intermittently. Always confirm the definition for your brand with a compatible scan tool.
Can I drive with a P1100 code?
Yes. The severity is low and most drivers notice no symptoms, apart from slightly less power at high altitude. Still, have the sensor circuit checked so the code does not hide other problems.
How much does it cost to fix P1100?
On a Toyota the cost runs from $0 to about $600. It costs nothing if the problem is a loose connector, and more if the computer has to be replaced.
Will a P1100 code clear itself?
The check engine light may go out after several drive cycles without the fault, but the code stays in memory history. If the cause is a bad sensor or connection, it will come back.
What is the most common cause of P1100?
The barometric sensor itself, or its internal circuit in the computer. Check the power supply, grounds and connector first, since they are cheap to rule out.

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Questions about the P1100 code

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