Ford must carry out a major recall, that of 552,188 units of the F-150 pickup truck of the year 2014. The problem concerns a transmission defect which can lead to unexpected downshifts in first gear, while the vehicle is traveling at any speed.
This is a situation that can be worrying, for example at highway speeds.
Nature of the problem
According to Ford’s recall report, “certain vehicles may experience intermittent loss of signal from the output shaft speed sensor (OSS) to the powertrain control module (PCM), which could result in a temporary downshift and involuntary in first gear.
This transmission problem can cause a loss of control of the vehicle or even immobilize it. It is attributed to a faulty transmission sensor.
Identified causes
Ford has identified several possible causes for OSS signal issues, including contamination, short circuiting, connector corrosion, and incorrect OSS sensor outputs. Due to this diversity of causes, there is no single solution to directly address the problem.
The age of the vehicle certainly plays a role in the nature of this problem, which did not manifest itself during the vehicle’s first few years on the market. One can guess that better preserved models may be less at risk, but this is just speculation.
Proposed solution
To correct the problem, Ford will update the shift logic to include a “plausibility check.” This check will ensure that the speed indicated by the OSS sensor is consistent before automatically ordering a downshift to first gear.
This software update aims to prevent unintentional downshifts that could cause accidents.
Impact
Ford’s report does not indicate irreparable damage to the powertrain resulting from this problem. However, he mentions several incidents where the rear wheels of the vans locked and the driver lost control.
Owners of affected models are advised to wait for notification from Ford before having their F-150 repaired. These should be sent from the beginning of July.
Those who have previously completed repairs related to this issue outside of the warranty coverage period may be eligible for a refund.
Original content from auto123.
