The C1711 error code is a common issue for Toyota Land Cruiser owners equipped with Active Height Control (AHC). This code indicates a problem with the front left height control sensor, often manifesting as inaccurate readings or a complete failure. This article explores how to diagnose and resolve the C1711 error, drawing upon a real-world example from a Land Cruiser forum.
A forum user reported experiencing confusing height sensor readings, specifically a front left reading of -14.8mm while the vehicle appeared level. This significant deviation from the expected “close to zero” reading (within +/- 5mm) strongly suggests a faulty sensor. The user’s plan to replace the right height sensor, while potentially necessary, might not address the core issue indicated by the C1711 code: the front left sensor.
Diagnosing the C1711 Error
Before replacing any parts, it’s crucial to perform a thorough diagnosis. The first step is to ensure the vehicle is cross-leveled. This involves confirming equal hub-to-fender distances on both front sides, adjusting with torsion bar adjusters if necessary. Note that front height control sensor adjusters cannot be used for cross-leveling due to the hydraulic interconnectedness of the front AHC system.
After cross-leveling, recheck the height sensor readings. Persistently abnormal readings on the front left sensor confirm the C1711 diagnosis. While the user in the forum example ordered a right-side sensor, the focus should be on the problematic left-side sensor.
Addressing the Faulty Sensor
With the C1711 confirmed, the next step is to inspect the front left height control sensor. With the ignition on, engine off, and ELMscan (or Techstream) connected, attempt to adjust the sensor using the sliding adjuster to achieve a reading as close to zero as possible. This process may require a hoist or ramps for safe access.
If adjustment fails to produce a near-zero reading, the sensor is likely faulty and requires replacement. When installing a new sensor, note the temporary plastic pin often found on new sensors with linkage. This pin indicates the factory “N” height setting. Adjust the sensor to match this position initially, then fine-tune for a zero reading after installation, even if it requires breaking the pin.
Confirming the Repair
After replacing the sensor, re-check the readings and ensure proper AHC functionality. Resources like the “ABCs of AHC” thread on ih8mud.com and YotaMD’s “AHC Info” video offer invaluable guidance on correct AHC settings and adjustments.
It’s also essential to consider potential wiring harness damage, especially from rodents, as this can contribute to sensor malfunctions. Refer to the Land Cruiser Workshop Manual for detailed information on AHC system inspection and troubleshooting.
Addressing the C1711 error by replacing the faulty front left height control sensor, coupled with meticulous adjustments and system checks, will restore the proper function of your Land Cruiser’s AHC system.
