# MPU6050 returns all zeros or does not wake up

> Fix an MPU6050 that reads zeros: the sleep bit in PWR\_MGMT\_1, the I2C address 0x68 or 0x69, wiring and the AD0 pin.

Canonical: https://roboticsengineering.in/fix/mpu6050-returns-zeros-or-wont-wake/ | Published: 2026-11-03 | Updated: 2026-11-04

**The MPU6050 starts in sleep mode, so you must write to its power management register to wake it.** If you read the registers directly, do that first.

## What the message means

After power-up the chip sleeps and its data registers stay at zero. Libraries clear the sleep bit for you; hand-written code must write 0 to register 0x6B (PWR_MGMT_1).

## Fix it in this order

1. Run an I2C scanner. The MPU6050 answers at 0x68 (AD0 low) or 0x69 (AD0 high).
2. Write 0 to register 0x6B to wake it, or use a library that does this in begin().
3. Check SDA and SCL wiring, power (3.3 V or 5 V as your module allows) and ground.
4. Keep AD0 connected to a definite level, not floating.
5. Call the library begin() and check its return value.
6. Try a second module. Counterfeit or damaged boards exist.

## Why it happens

The MPU6050 powers up in sleep mode, which keeps its measurement registers at zero. Its power management register at address 0x6B holds the sleep bit, and writing 0 to that register wakes the chip and starts measurement. Most libraries do this inside begin(), but hand-written code must do it explicitly, or every read returns zeros.

The chip also has to answer on the I2C bus, at 0x68 or 0x69 depending on the AD0 pin. A floating AD0 can leave the address unstable, and a loose connection or weak supply can leave the chip unresponsive. An I2C scanner shows whether the chip responds at all, which separates a wake-up problem from a wiring fault.

## If you see this, do this

| You see | Do this |
| --- | --- |
| Scanner finds nothing | See the I2C page. |
| Found at 0x68 but data are zero | The chip is asleep. |

## Confirm the fix

1. Run an I2C scanner and confirm an address of 0x68 or 0x69 appears in the output.
2. Write 0 to register 0x6B, read it back, and confirm the value is 0 before you read any sensor data.
3. Read the accelerometer registers with the board lying flat; one axis should show a value near gravity, not all zeros.

**Common mistake:** Assuming the sensor is broken when every reading is zero. The chip powers up asleep and needs a wake-up write before it reports anything.

## Related

[MPU6050 gyro drift](https://roboticsengineering.in/fix/mpu6050-gyro-drift-calibration-offset/), [I2C device not found](https://roboticsengineering.in/fix/i2c-device-not-found-arduino-esp32/), [complementary filter](https://roboticsengineering.in/complementary-filter-imu-arduino/).

Last reviewed: November 2026. These are the usual causes and the order that finds them fastest. Test on your own board; clones and cables differ.

## Why this happens

At power-up the MPU6050 is in sleep mode. The PWR_MGMT_1 register at address 0x6B resets to 0x40, with bit 6 set, which is the sleep bit. While it is set the sensor stays idle and the data registers stay at zero. Writing 0 to that register clears sleep and starts measurement.

The chip is found on the I2C bus at 0x68, or at 0x69 if AD0 is high. So the chip can answer a scan and still return zeros, because I2C working only shows the chip is present. A fault in the bus itself looks different: the scanner finds nothing, or the first read returns an error.

## How to confirm the cause

- Run an I2C scanner. If 0x68 or 0x69 appears, wiring and addressing are fine and the problem is configuration.
- Read the WHO_AM_I register at 0x75. A genuine MPU6050 returns 0x68. A different value, for example 0x70, suggests a different chip such as an MPU6500 sold under the same name.
- Read register 0x6B. A value of 0x40 means the chip is still asleep.
- After writing 0 to 0x6B, read it back. If it does not read 0, the write is not reaching the chip.
- Lay the board flat and read the Z acceleration. At the default range the raw value should be near 16384 for 1 g.

## Worked example

This sketch wakes the chip and prints the Z acceleration in g. At the default plus or minus 2 g range, 16384 raw counts equal 1 g.

```
#include <Wire.h>
void setup() {
  Serial.begin(115200); Wire.begin();
  Wire.beginTransmission(0x68); Wire.write(0x6B); Wire.write(0); Wire.endTransmission(true);
}
void loop() {
  Wire.beginTransmission(0x68); Wire.write(0x3B); Wire.endTransmission(false);
  Wire.requestFrom(0x68, 6, true);
  int16_t ax = (Wire.read() << 8) | Wire.read();
  int16_t ay = (Wire.read() << 8) | Wire.read();
  int16_t az = (Wire.read() << 8) | Wire.read();
  Serial.println(az / 16384.0);
  delay(500);
}
```

A board lying flat should print a value close to 1.0. A value that is exactly 0 means the chip is still asleep or the read failed.

## Common mistakes

- Checking only that the scanner finds the address and calling the sensor good.
- Leaving AD0 floating, so the address changes at random.
- Mixing up raw counts and units, and reading 16384 as a fault.
- Reading only one byte of each two-byte value.

## If this did not fix it

- Counterfeit or different chip: check WHO_AM_I and use a library written for that chip.
- Supply voltage: confirm the module’s input range and use the right one.
- Pull-ups missing on a bare chip: add resistors to SDA and SCL.