How SDD has changed the future of Land Rover diagnostics?
26th June 2016
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Making SDD effective when selecting Vehicle symptoms for your Jaguar & Land Rover

SDD is designed to link DTCs and provide recommendations based on Customer Facing and/or the most significant symptoms. Do not try to short-cut or refine the customer’s reported symptoms based on expected failures. If the primary or most obvious Customer Facing symptom is an MIL or message center warning, those symptoms MUST be included in your symptom selection inputs using SDD. While it might seem logical when selecting ‘Air Suspension is inoperative’ that there is really no need to select the symptom ‘Message center warning’, it is important to do so. Otherwise SDD may exclude DTCs or recommendations that relate to failures known to trigger a warning message or MIL. Be sure to select any additional symptoms observed during a road test in addition to the most obvious symptoms and customer reported info. Altering the selected symptoms adjusts the filtering of the DTCs. Selecting fewer symptoms makes the filter ‘coarser’ while selecting more symptoms makes the filter ‘finer’.

If very few or no DTCs and recommendations are

listed, try restricting your symptom selections to Level 3 in the symptom tree.

If too many DTCs or recommendations are listed, try

selecting symptoms to Level 4 or 5, using care not to select an inaccurate symptom.

To be sure that you are only working with your

intended symptom list: open the ‘Selected Symptoms’ drop down box at the upper right portion of the Symptom Selection tab to review all currently selected symptoms. Avoiding Common SDD Symptom Selection Errors Powertrain > Engine system > Starting system > Start-stop system: Note that the Start-Stop System is a fuel conserving technology used on diesel vehicles sold in other markets. This is not associated with the ‘Start Button’ used to actuate the ignition on Smart Key equipped vehicles. Warning Lamps, Status Lamps, and Message Center Use care when entering symptoms related to customer complaints of MIL lights and warnings. When a light and a message are reported or observed, both of these symptoms must be included. When viewing the symptom categories within the Electrical > Instrument Cluster section, there are 3 classes of ‘driver information’ symptoms:

Warning Lamps (red)
Warning Messages (in Message Center)
Status Lamps (yellow)

While it is easy to distinguish between a Warning Message and a Warning Lamp that is currently active, if the problem is intermittent, the service writer must determine through careful questioning of the customer if a warning lamp, warning message, or both were displayed. Also, not every MIL is considered a Warning Lamp since some indicators on the instrument cluster are used to indicate the status of a system. Examples of Status Lamps include the Passenger Seat Occupancy Status Lamp and the TPMS Status Lamp. Using the Passenger Seat Occupancy Status Lamp as an example: this light is only used to indicate the status of the passenger seat. When lit, it simply indicates that the SRS system has determined that based on the current inputs, the passenger restraints will not be deployed. It does not mean the system has detected a failure that requires a driver warning. For this reason, the lamp is classified as a Status Lamp. Similarly, the amber TPMS indicator is used to inform the driver that the tire pressure requires attention. While this light may remain lit when a system malfunction exists, it is considered a Status Lamp since its primary function is to inform the driver of the tire pressure status. Recommendation: When selecting SDD symptoms for lamps that are primarily considered a Status Lamp, but are also known to have a secondary function as a Warning Lamp, be sure to select the symptoms under both categories in the symptom selection map.

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