Navigating the complexities of modern automotive technology often presents unique challenges, and the Direct Adaptive Steering (DAST) system in the 2017 Infiniti Q50 is no exception. As an auto repair professional, I recently encountered a perplexing situation while attempting a DAST calibration on this model. This article aims to share my troubleshooting experience, specifically focusing on performing a successful 2017 Infiniti Q50 DAST calibration with a scan tool Consult, and potentially save fellow technicians from similar frustrations.
For those unfamiliar, Infiniti’s DAST, also known as “steer-by-wire,” is an advanced system that replaces the traditional mechanical linkage between the steering wheel and the wheels with electronic controls. The DAST system comprises several key components working in concert:
- DAST Control Modules (typically Module 1, Module 2, and Module 3 which is integrated with the EPS – Electronic Power Steering)
- Steering Angle Main and Sub Actuators (located on the steering rack)
- Steering Force Actuator (on the steering column)
- Steering Clutch (responsible for coupling the steering shaft)
The Case: DAST Calibration Setback
The 2017 Infiniti Q50 in question presented a peculiar history. The owner reported lending the vehicle, after which a bizarre electrical issue surfaced. The Body Control Module (BCM) seemed to malfunction, preventing the vehicle from shutting off, rendering the start/stop switch unresponsive, and causing a complete loss of electrical functions such as door locks and windows. To power down the car, the battery and alternator had to be manually disconnected.
Upon restoring power, clearing the diagnostic trouble codes (DTCs) resolved the body electrical malfunctions. However, the DAST system was now out of calibration. It’s hypothesized that during the electrical anomaly, the steering clutch decoupled, resulting in the steering being misaligned by approximately 200 degrees. This misalignment led to limited power steering assist and DAST booting angle processing codes. Consequently, cascading DTCs were triggered in the ABS (Anti-lock Braking System) – code C1138, and the ICC/ADAS (Intelligent Cruise Control/Advanced Driver Assistance Systems) – code C1A04.
It’s important to note two crucial points before proceeding further:
- Manual Steering Correction Procedure: Infiniti provides a manual procedure for minor DAST steering corrections. This involves a power cycle combined with steering wheel movements and driving, designed to incrementally correct an off-center steering wheel during normal vehicle operation. However, this method was insufficient for the severe misalignment in this case.
- Service Bulletin ITB18-021: Infiniti issued service bulletin ITB18-021 addressing incomplete DAST calibration issues. This bulletin essentially mirrors the electronic service manual (ESM) procedure but offers enhanced clarity and guidance specifically for troubleshooting calibration problems.
Initial Calibration Attempts and Roadblocks
My initial approach was to perform the DAST calibration mode 1, which requires alignment turntables. This calibration sequence initiates a system self-check where the steering system steers left and right to determine its range and center. Subsequently, the steering clutch decouples at the steering range center, allowing the technician to mechanically center the steering wheel as needed before finalizing the calibration. This was the standard procedure I aimed to execute.
Equipped with multiple professional-grade scan tools – Autel, Launch, Topdon, and Snap-on – all boasting DAST calibration capabilities, I attempted the procedure. However, each tool consistently returned errors such as “unable to complete” or “conditions not correct.” Suspecting a potential limitation with aftermarket tools, I resorted to the factory diagnostic system, Consult III+ (C-III+), but encountered the same frustrating outcome.
The Configuration Revelation
Returning to the fundamentals, I revisited step one of the troubleshooting process. Following the guidance in the TSB and ESM, the initial step for DAST calibration is to configure all three DAST modules and, if equipped, the CAN gateway module (which this particular Q50 included). The ESM directs technicians to the configuration procedures, emphasizing acquiring the “type ID” from each module and verifying it against the FAST (Fast Assessment Scan Tool – service parts catalog) system. A quick call to the local Infiniti parts department provided the necessary type IDs for all pertinent modules. The subsequent configuration step involves comparing the read type IDs with the FAST type IDs to ensure agreement. Further configuration steps address module replacement and configuration writing, with a caution to only replace control modules when absolutely necessary, as the ESM procedure is primarily framed around module replacement scenarios.
Herein lay my critical oversight: Upon comparing the module type IDs, they all matched the expected values. Consequently, I mistakenly assumed (a classic pitfall in diagnostics!) that the module configurations were correct and therefore unnecessary. I prematurely proceeded to the subsequent DAST calibration steps.
Realizing my potential error, I returned to the C-III+ system and performed the configuration write procedure for all DAST modules and the CAN gateway module, despite the type IDs already matching. Attempting the calibration again after configuration write, disappointingly, yielded the same “calibration failed” error.
Breakthrough: The Calibration Incomplete DTC
DAST calibration is designed to be contingent on the absence of any related DTCs. Reasoning that the module configuration process might have inadvertently set communication-related DTCs in other modules, I disconnected the C-III+ and connected the Autel Ultra. The Autel Ultra was chosen for its speed and efficiency in performing a full system scan and DTC clearing. As anticipated, the scan revealed U-codes (communication fault codes) across nearly every module. Crucially, a new DTC, “DAST calibration incomplete,” was now present in DAST module 3. AHA! This was the pivotal clue. Performing the module configurations, or in this case, re-configurations, had seemingly placed the DAST system into a specific state where it would now accept calibration.
With all DTCs cleared, only the original codes related to the initial DAST issue and the newly generated “calibration incomplete” code remained. Leaving the Autel Ultra connected, I re-initiated the DAST mode 1 calibration. This time, the calibration sequence progressed smoothly and completed successfully without any errors. Following calibration, I performed the steering angle sensor position learning procedure and cleared all DTCs. All diagnostic codes were resolved, and the 2017 Infiniti Q50’s steering system returned to normal operation.
Tech Tip for DAST Calibration Success
The key takeaway from this experience and troubleshooting process is this crucial tech tip: even if the read type IDs of the DAST modules match the expected values, ensure you proceed with the module configuration write procedure to enable DAST calibration. This step appears to be essential in preparing the system to accept and complete the calibration process, especially after certain electrical or system disruptions.
As a final note, while I utilized the Consult III+ for the configuration write procedure, it’s worth mentioning that aftermarket scan tools from Autel, Launch, and Topdon also claim the capability to read and write these module configurations. Therefore, in similar scenarios, technicians may be able to complete the entire DAST calibration process using a single, well-equipped aftermarket scan tool, streamlining the repair workflow.
Hopefully, sharing this experience assists other technicians facing similar challenges with 2017 Infiniti Q50 DAST calibration with a scan tool Consult or other compatible diagnostic tools.
