F150 Traction Assist and Power Steering Fault
2013 F150 - Presents with Traction assist warning in instrument cluster and DTC’s C1B00:62 in the PSCM and U0428 in the ABS module
Technical support was requested for ABS module reprogramming per TSB 12-11-18. This tsb does not apply to this model year. Ford programming software does not have the function for ABS software updates on this model year.
Previous repairs – steering rack replaced and programmed 6 months ago for C1B00 and U0428
Performed normal visual inspections no abnormalities seen, no looseness in suspension or aftermarket electronics.
Ford service information can be difficult to navigate for specifics on some system operations. Power Steering Control Module (PSCM) diagnostics are listed as interactive guided diagnostics on this model year. Following the diagnostic process outlined, Inspect the network wiring and test powers and grounds at the rack. Check for terminal issues, none were found. If symptom returns, replace the rack which includes the PSCM.
The customer installed the second rack in 6 months for this same issue. Almost immediately during the road test the warning for assist disabled and DTC’s C1B00 and the U0428 are triggered as well.
So, where did we go wrong?
The power of the PSCM was monitored (via pid) for loss of voltage under load during dry steering, to load the high current electrical circuits. The network wiring was verified to have proper can network patterns at the PSCM. Terminating resistance was checked at the PSCM with the battery disconnected for good measure and found to be just over 60 ohms. When reading the dtc information description, we can infer that there may be additional things that would influence this fault. The manual reads: DTC C1B00:62 (Steering Angle Sensor: Signal Compare Failure) - This DTC sets if the calculated signal does not match other sensor inputs. We monitor the steering wheel position in the Steering column control module (SCCM) and in the Anti-Lock Brake (ABS) module as well. The steering angle reads normally at times, -600° to 600°, but gets stuck at 0° intermittently. When the vehicle is shut down and restarted normal operation resumes. Data in the PSCM was normal always reading from approx. -600° to 600°
The steering wheel position sensor, part of the clock spring, was replaced for this concern with no change in data or symptom.
Reading more into the description and operation of the Advance Trac or ABS system we find that the 5.0 F150 does not have a steering wheel position sensor, the 6.2 (Raptor) version has an integrated wheel position sensor in the clock spring. The dealer sold them a clock spring unaware that there was no position sensor on that specific part. For all other applications, the steering wheel rotation sensor is part of the PSCM. The sensor is serviced with the PSCM. The PSCM uses the HS-CAN to transmit information to the ABS module about steering wheel turning direction (left or right) and how far it is being turned. The PSCM does not indicate the absolute position of the steering wheel relative to straight-ahead. The ABS module learns this position by comparing the steering wheel position with other signals and storing the position it has learned. The ABS module confirms this position and modifies it as necessary during every new driving cycle.
The tires initially were a matched set of four with 2 worn severely. 2 tires were replaced. Road testing if the vehicle verified all 4 wheel speed sensors matched at 50 mph and no erratic accelerometer readings either.
This put us in the position to need a THIRD steering rack.
When the third replacement rack had arrived, it was inspected for correct application and was the same part as the previous replacements. The rack was also checked for any shipping damage, paying close attention to the ends of the box for damage if dropped on the end during shipping. After the installation of the most recent rack the faults have been resolved and correct live data reading have been restored. Intermittent loss of steering angle on the network was creating the issues.
Chris, First off, thank you for the write up, I appreciate the time and effort that goes into them. I have a question with no correct answer here. I always hate having to replace a recently replaced part, even when I've proven it is failed, something in my gut makes me start looking for a missed cause of failure. My question is, in your opinion, would diagnosing failures like this benefit
In short, yes. Being able to monitor multiple modules at the same time and having a full understanding of system operation is imperative with issues such as this. Ford does provide excellent description and operation compared to many manufacturers, but it still requires making some inferences. Knowing what is being read directly and what is being broadcast via network or even through a gateway
Chris, As the other Chris pointed out system operation knowledge is a must. But, that only goes so far some times. You have to think on your feet as well. I was presented with a 2012 Ford Focus with Traction lamp on and power steering issues. A used rack (PSCM) was installed and then a remanufactured rack (PSCM) was installed with the same result. Vehicle would have power steering then when
John & Chris, Thank you both for the insight. I run HD during the day, and my personal business is mobile diagnostics at night. I often get anxious when making inferences and feeling like I am missing some obscure variable, some input that could skew the whole result but isn't clearly described. Glad to hear that I am not the only one, and that I'm not in the wrong by reasoning and making