DATALOGGER Misfire Signal Advice (SSM72336)

Publication date: 2016-05-12
Reference number: SSM72336

DATALOGGER MISFIRE SIGNAL ADVICE

TECHNICAL SERVICE BULLETIN

Reference Number(s): SSM72336, Date of Issue: 12-May-2016

JAGUAR:	F-PACE/X761; F-TYPE/X152; S-TYPE/X200; X-TYPE/X400; XE/X760; XF/X250; XF/X260; XJ/X350; XJ/X351; XK/X100; XK/X150
SECTION:	Diagnostic Software Hardware

SERVICE INFORMATION

Symptom 000101 Diagnostic Concerns

Powertrain - Misfire - Cylinder Identification application

The new 'Powertrain - Misfire - Cylinder Identification' application is available for JLR vehicles built from 2010 model year onwards fitted with a petrol engine. The application uses the vehicle data and automatically configures the onscreen engine layout.

NOTE: The new application will only identify the location of the misfire, it will not identify the cause. The technician must investigate the cause by using suitable diagnostic techniques and methods.

Further information is available in:

The SDD Personal Study Module (PSM) 'Lesson 3 - SDD Features and Functions' available in the Excellence Academy training area.
Issue 5 of the SDD Newsletter

Since this new application within SDD is engineered to accurately report misfire counts for all engine variants, it is the currently recommended diagnostic aid when investigating misfire related symptoms or DTC's.

The original advice in this SSM is retained below for reference only.

ISSUE

When using SDD's datalogger application to view live engine misfire data, there are numerous types of signals with different behavior dependent on model year, vehicle and engine type. This can often lead to confusion and misinterpretation of data during the diagnostic or repair validation processes.

CAUSE

The specific implementation of misfire monitoring strategy engineered into each vehicle/model range determines the related signals offered and behavior observed when using SDD.

SOLUTION

For this reason, the following advice regarding all engine misfire signals in datalogger is offered:

When the specific Misfire signals offered include detailed on-screen help text:

Technicians can rely upon those signals' data and behavior as per the provided help text. They are signals that have been fully validated and documented.

When the specific Misfire signals offered DO NOT include detailed on-screen help text:

Technicians must use those signals with caution as undocumented data, unless following guidance from a related technical publication or other specific directions from JLR technical support staff.

KNOWN CONCERNS - AJ126 V6 Engines:

There are numerous misfire related datalogger signals available for these vehicles known to have misleading cylinder numbering references. Currently the ONLY signals on these vehicles that use the correct alignment with the DIN specification of these engines for both DTC's and physical location are titled "Misfire cylinder # data - Test Value". However, please note that these signals can display misfire counts on both a misfiring cylinder and its "companion" cylinder firing 180 degrees away from it, when only one of them are currently misfiring.