YXZ Addicts Tech

ECU Fault Codes

A fast Yamaha YXZ reference for fault-code definitions, expandable diagnostic videos, and related technical resources.

Fast reference: A fault code identifies the system that needs testing; it does not automatically prove the named component has failed. Cards marked Tech Resource include an expandable video guide.

08

Code 08

Gear-position sensor circuit is open or shorted.

12

Code 12

The ECU is not receiving a normal crankshaft-position signal.

Tech Resource

Code 12 Diagnostic Guide

Choose the path that matches what the machine does when you turn the key.

Factory definition: No normal signal is received from the crankshaft-position sensor.

No Crank + Code 12

Begin with the battery, cables, grounds, fuses, starter relay, wiring, starter motor, and the rest of the cranking circuit.

Cranks + Code 12

Inspect the crankshaft-position sensor, connector, wiring, and signal circuit before replacing components.

Test Before Replacing

A stored Code 12 does not automatically prove that the starter or crankshaft-position sensor has failed.

Related Used Starter
13

Code 13

Intake-air-pressure sensor 1 circuit is open or shorted.

Tech Resource
14

Code 14

Intake-air-pressure sensor 1 hose may be clogged, loose, or disconnected.

Tech Resource

Codes 13 & 14 Sensor 1 Guide

Separate an electrical circuit fault from a hose or pressure-reading fault.

Definitions: Code 13 indicates an open or shorted sensor circuit. Code 14 indicates an abnormal pressure reading that may be caused by a clogged, loose, disconnected, or damaged hose.

Code 13

Inspect the sensor 1 connector, wiring, supply, ground, and signal circuit.

Code 14

Inspect the sensor 1 pressure hose for blockage, damage, looseness, incorrect routing, or disconnection.

Identify Before Testing

The video identifies both intake-pressure sensors so the correct hose and circuit are tested.

15

Code 15

Throttle-position sensor circuit is open or shorted.

21

Code 21

Coolant-temperature sensor circuit is open or shorted.

22

Code 22

Intake-air-temperature sensor circuit is open or shorted.

25

Code 25

Intake-air-pressure sensor 2 circuit is open or shorted.

Tech Resource
26

Code 26

Intake-air-pressure sensor 2 hose may be clogged, loose, or disconnected.

Tech Resource

Codes 25 & 26 Sensor 2 Guide

Separate an electrical circuit fault from a hose or pressure-reading fault.

Definitions: Code 25 indicates an open or shorted sensor circuit. Code 26 indicates an abnormal pressure reading that may be caused by a clogged, loose, disconnected, or damaged hose.

Code 25

Inspect the sensor 2 connector, wiring, supply, ground, and signal circuit.

Code 26

Inspect the sensor 2 pressure hose for blockage, damage, looseness, incorrect routing, or disconnection.

Identify Before Testing

The video identifies both intake-pressure sensors so the correct hose and circuit are tested.

30

Code 30

A rollover or latch-up condition was detected.

33

Code 33

Ignition-coil 1 primary circuit is open or shorted.

34

Code 34

Ignition-coil 2 primary circuit is open or shorted.

35

Code 35

Ignition-coil 3 primary circuit is open or shorted.

37

Code 37

Engine speed is high while the engine is idling.

Tech Resource

Code 37 High-Idle Guide

The diagnostic path changes according to whether the ISC operates during testing.

Factory definition: Engine speed is high while the engine is idling.

ISC Operates

Verify the throttle valve and linkage close fully, then inspect clamps, cable, hoses, and nearby components for contact or binding.

ISC Does Not Operate

Follow the electrical path for the ISC circuit, including connector, wiring, power supply, ground, and actuator operation.

Video Example

The video demonstrates a rotated throttle-body clamp interfering with the linkage and creating a high-idle condition.

39

Code 39

Fuel-injector circuit is open or shorted.

41

Code 41

Lean-angle sensor circuit is open or shorted.

42

Code 42

Speed-sensor signal is missing, or a neutral/clutch-switch circuit fault was detected.

43

Code 43

Incorrect supply voltage is reaching the fuel injector or fuel pump.

44

Code 44

The ECU encountered an EEPROM read/write error.

46

Code 46

Charging-system voltage is outside the normal range.

50

Code 50

ECU memory fault.

85

Code 85

Oil-pressure-switch circuit is open or shorted.

92

Code 92

PCV-solenoid circuit is open or shorted.