The Quick Answer above is the generic definition. What follows is the model-specific detail for the Toyota models that log P0100.
DTC/P0100·Toyota
P0100 on Toyota: Causes, Symptoms and Fix Cost
Quick Answer
Moderate SeveritySafe to drive (short-term)Toyota
P0100 on a Toyota means the engine computer has lost a usable signal from the mass air flow (MAF) sensor circuit, the sensor in the intake that measures how much air the engine draws in. Unlike P0101, where the sensor works but reads implausibly, P0100 points at the circuit itself: missing power or ground, a broken or shorted signal wire, a corroded plug or a dead sensor. The engine switches to a backup airflow estimate, so it runs less smoothly, uses more fuel and, on many diesels, loses power.
Connect any standard Bluetooth OBD2 adapter to your Toyota and Skanyx tells you what P0100 means on that engine, whether it is safe to keep driving, and what the fix should cost. Free on iPhone and Android.
Get Skanyx freeWhat does P0100 mean on a Toyota?
Toyota RAV4 2.4 (2AZ-FE)
2004-2012RAV4s with the 2.4 litre 2AZ-FE petrol use a hot-wire MAF meter, and Toyota's repair manual sets P0100 when its output stays below 0.2 V or above 4.9 V for 3 seconds. A live reading of about 0 g/s points to an open power feed or signal wire, while 271 g/s or more points to an open sensor ground. While the code is set the engine runs in fail-safe, with ignition timing calculated from engine speed and throttle position.
What causes P0100 on a Toyota?
Beyond the generic causes listed on the main P0100 page, these are the patterns noted for Toyota models:
Toyota RAV4 2.4 (2AZ-FE)Open power feed or signal wire at the hot-wire MAF meter, reading about 0 g/s
Toyota RAV4 2.4 (2AZ-FE)Open MAF meter ground circuit, reading 271 g/s or more
How to diagnose P0100 on a Toyota with OBD2
Follow these steps to pinpoint the root cause of P0100:
- Read every stored code. P0100 together with other sensor or supply-voltage codes points to a shared power feed, relay or ground rather than the MAF sensor itself
- Read the live MAF value (the standard OBD2 airflow reading, in grams per second) with the engine idling. A warm four-cylinder petrol typically shows roughly 2 to 7 g/s. A value stuck at zero, or pinned at an impossible maximum, while the engine runs points to the circuit fault. On some cars the reading shows the engine computer's substitute value while the code is active, so a plausible number does not clear the circuit on its own
- Inspect the MAF connector: look for a broken locking tab, green corrosion, water in the plug or pushed-back pins. Wiggle the harness while watching the live value; a reading that jumps as you move it is a wiring fault
- Backprobe the connector with the key on. Check for supply voltage (battery voltage on many hot-film sensors, a 5 V reference on some), a good ground (within about 0.1 V of battery negative), and a signal that changes when the engine runs
- If the supply is missing, check the fuse and relay that feed the sensor, then the wire between them and the plug
- If supply and ground are good but there is no signal, check the signal wire for continuity to the engine computer. If the wire is intact, replace the MAF sensor
- Clear the code and test drive with some firm acceleration. On a diesel, confirm that full power has returned and the code does not come back
How much does P0100 cost to fix on a Toyota? (EUR)
Estimated repair costs for P0100 in EUR, compiled across makes. Toyota costs typically sit in the middle of each range.
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
Codes related to P0100
These codes are often seen alongside P0100 or point to related issues, on any make:
Looking for the full P0100 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0100 guideSkanyx · Toyota
Diagnose P0100 on your Toyota
Your car logged P0100. Skanyx reads it on any standard Bluetooth OBD2 adapter, tells you whether it is safe to keep driving, and breaks down the likely repair so you know the number before a shop quotes you. Free on iPhone and Android, and you do not need to be a mechanic to read it.
Get Skanyx free