Direct Adaptive Steering (DAST), Infiniti’s steer-by-wire system, can sometimes present unique challenges during calibration. Recently, I encountered a perplexing situation with a 2017 Infiniti Q50 that refused to complete DAST calibration, despite using multiple professional scan tools. Sharing this experience might save fellow technicians from similar headaches when tackling a 2017 Infiniti Q50 DAST calibration with a scan tool.
For those unfamiliar, the Infiniti DAST system is a complex network involving several key components. These include DAST module 1, DAST module 2, DAST module 3 (which integrates the Electronic Power Steering or EPS), steering angle main and sub actuators located on the steering rack, a steering force actuator on the steering column, and a steering clutch that mechanically links the steering shaft when needed.
The vehicle in question had a peculiar history. The owner reported that after lending the car, the Body Control Module (BCM) seemed to malfunction. This resulted in the vehicle being unable to shut off, no response from the start/stop switch, and a complete loss of electrical functions like door locks and windows. To power down the car, the battery and alternator were disconnected. Upon restoring power, clearing generic U-codes resolved the body function issues. However, the DAST system was now out of calibration. It appeared that during this electrical anomaly, the steering clutch had decoupled, causing the steering to be misaligned by approximately 200 degrees. This led to limited power steering assist and DAST booting angle processing codes, subsequently triggering codes in the ABS (C1138) and Intelligent Cruise Control/Advanced Driver Assistance Systems (ICC/ADAS – C1A04) as a cascading effect.
It’s worth mentioning two points before diving deeper. Firstly, Infiniti provides a manual DAST steering correction procedure. This involves a sequence of power cycling, steering maneuvers, and driving, designed to correct minor steering wheel off-center issues during normal driving. However, this procedure was insufficient for the severe misalignment in this case. Secondly, Infiniti has issued a service bulletin (ITB18-021) addressing incomplete DAST calibration. This bulletin essentially mirrors the electronic service manual (ESM) procedure but offers additional clarity and guidance specifically for troubleshooting calibration problems.
DAST calibration mode 1, the procedure I was attempting, is typically performed on alignment turntables. When initiated, the system automatically steers left and right to determine its operational range and center point. Crucially, it then decouples the steering clutch at the steering range center, allowing a technician to manually center the steering wheel as needed before completing the calibration. This was the exact procedure that was proving problematic.
Frustratingly, every scan tool at my disposal – Autel, Launch, Topdon, and Snap-on – which all claim to support DAST calibration, failed to complete the process. Each tool returned errors like “unable to complete” or “conditions not correct”. Suspecting a potential issue with aftermarket tools, I even resorted to using the factory Infiniti diagnostic tool, C-III+, but encountered the same “calibration failed” result.
At this point, I had to revisit the fundamentals and consider what I might be overlooking. It was clearly a procedural issue on my end.
Referring back to the TSB procedure, the very first step for DAST calibration step 1 is to configure all three DAST modules and, if equipped, the CAN gateway module (which this particular Q50 had). The procedure directs you to the ESM for detailed configuration steps. This initial configuration involves retrieving the “type ID” from each module and comparing it against the parts information in the Infiniti FAST (service parts catalog) system. A quick call to the local Infiniti parts department can provide the correct type IDs for all relevant modules. The second part of this configuration step is to verify that the read type IDs from the vehicle modules match the expected type IDs from FAST. Subsequent configuration steps address module replacement scenarios and configuration writing, with a cautionary note to “replace control modules only when necessary,” as the ESM configuration procedure is primarily written from a module replacement perspective.
Herein lay my critical error. Upon comparing the module type IDs, they all matched the expected values. I mistakenly assumed (and we all know what assuming does!) that the module configurations were therefore correct and didn’t require any further action. Consequently, I skipped the module configuration step and proceeded directly to DAST calibration.
Using C-III+ again, I went back and deliberately performed the configuration write procedure for all DAST modules and the CAN gateway module, even though the IDs matched. Despite this, attempting the calibration again resulted in the same frustrating failure.
It’s important to remember that DAST calibration cannot be successfully performed if any related Diagnostic Trouble Codes (DTCs) are present. I reasoned that forcing the module configurations might have inadvertently set communication-related DTCs in other modules. Therefore, I disconnected C-III+ and switched to the Autel Ultra, primarily for its speed and user-friendliness in performing a system-wide scan and DTC clearing. As anticipated, U-codes were present in nearly every module. More significantly, a new DTC, indicating a DAST calibration incomplete fault, had appeared in DAST module 3. AHA! This was progress. Performing the module configurations, or in this case, re-configurations, seemed to put the DAST system into a state where it was ready to accept calibration.
After clearing all DTCs, the only remaining codes were the original DAST related codes and the newly generated calibration incomplete code.
With the Autel Ultra still connected, I returned to the DAST mode 1 calibration function, initiated it, and this time, it proceeded flawlessly through all the steps. I then performed the steering angle sensor position learn procedure, cleared DTCs again, and all DTCs were finally gone. The car’s steering was back to normal, and the issue was resolved.
The key takeaway, the tech tip from this experience, is this: even if your scan tool indicates that the read module type IDs match the expected values, diligently follow through with the module configuration write procedure as outlined in the service manual to properly enable DAST calibration.
As a final note, while I used C-III+ to perform the module configurations, Autel, Launch, and Topdon tools are also capable of reading and (supposedly) writing these configurations. If you encounter a similar DAST calibration issue on a 2017 Infiniti Q50 or similar models, you might be able to complete the entire process using just one of these aftermarket scan tools, provided you ensure to perform the module configuration step before attempting calibration.
Hopefully, this detailed account will be helpful (HTH) to other technicians facing similar DAST calibration challenges.
