What does it mean?
P1564 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Idle Speed Control Throttle Position Low Voltage During Adaptation .
Symptoms
- Check engine light on and, on many vehicles, a throttle warning indicator
- Idle too high, too low, or hunting up and down after every start
- Engine stalls when lifting off the accelerator or when coming to a stop
- Poor throttle response and a delay between pedal input and engine reaction
- Engine drops into limp mode with reduced power
- Adaptation routine aborts or fails to complete on the scan tool
Likely causes
- Carbon deposits in the throttle bore preventing the plate from reaching its true rest position
- Worn or scored track in the throttle position sensor, giving a low output at closed throttle
- Low or unstable battery voltage while the adaptation was being carried out
- Corroded throttle body connector, or a high resistance 5 V reference and ground circuit
- Adaptation attempted with the wrong preconditions, for example a cold engine or electrical loads switched on
- Vacuum leak on the intake side, which forces the module to learn an incorrect idle position
- Replacement throttle body fitted without being coded or matched to the module
How to fix it
- Check battery voltage and charging output first, since a weak supply alone can abort adaptation
- Read the closed and wide open throttle position values in live data and compare them with the specified window
- Inspect the throttle connector and measure the 5 V reference and sensor ground at the harness side
- Clean the throttle bore and plate with an approved cleaner, following the manufacturer method
- Smoke test or otherwise check the intake for vacuum leaks that would distort the learned idle position
- Repeat the adaptation with all preconditions met: engine at operating temperature, accessories off, no load
- Replace and code the throttle unit if the sensor output stays out of range after cleaning