Throttle Control Unit Malfunction
The engine's throttle control system isn't communicating properly with the engine computer, like a broken remote control for your engine's air intake. The ECU can't adjust throttle position accurately, affecting engine performance and responsiveness.
The ECM monitors throttle position sensor voltage, throttle motor current, and electronically controlled throttle blade position. It compares actual throttle position against commanded position and detects communication faults or mechanical binding in the throttle actuator.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Throttle Position Sensor Voltage | 0.5V - 4.5V (proportional to throttle opening) | Out of range or erratic signal |
| Throttle Motor Response Time | Within 200ms to reach commanded position | Response delayed >500ms or no response |
Code P1600 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.
Once the fault is repaired, P1600 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.