Steve Rothwell answering your ENGINE MANAGEMENT queries
GENERAL
Q I have a ‘pro’ type diagnostics tablet which I have been using on various vehicles with each session lasting only a few minutes to retrieve codes or reset service indicators. I have seen reference to ‘battery support’ to be provided for longer sessions to ensure that anomalies are not raised by the battery voltage becoming lower.
I think there may be several ways to support the vehicle battery during a long session, but I have the following questions:
Can a ‘smart’ battery charger be used for the purpose and if so, would it have to be disconnected before starting the engine to view live data, etc?
It would be more convenient to use a lithium type jump-starter but given that it would normally be used for only a minute or two would it be OK for a 30-minute session?
Finally, if either of the above are not suitable can you suggest an alternative?
A Generally, battery chargers are not suitable for battery support unless they are specifically designed to give a stable and steady voltage. Jump cables from a second battery or a battery pack are also not recommended as they are unable to provide the required stable support.
The cost of battery support units is much higher than that of a standard charger/ conditioner with the lowest price unit I could find being the CTEK MXS 10EC 12V 10A Battery and Charger Support Unit at £195. The next option was the Sealey BSCU25 Battery Support Unit at £222 – and then the more professional units such as the GYSFLASH 30.12 PL which also incorporates a battery back-up system can be obtained for around £250.
It does really depend on the type of diagnosis that is needed, and the support units are really only required when conducting more involved coding, such as in the case of replacing a component where the code needs to be retrieved and then reprogrammed into the new or replacement unit.
JAGUAR X-TYPE
Q Just recently I was driving my 2008 Jaguar X-TYPE 2.2 diesel on the A45 – when I approached a roundabout I was in the wrong lane for my onward journey. I accelerated to enable me to enter the correct lane, and as I put my foot down the glow plug warning light came on, flashing repeatedly, and my speed restricted to a nominal 50mph.
When I could I pulled over, parked up and switched off. I restarted the engine and the glow plug light was extinguished and did not return. I continued at speed around 60mph, without incident.
I have had this issue in the past and it was fixed by replacement of the turbo actuator. This was some miles ago. Should I assume the same based on the recent events, would a diagnostic test prove that the electronic module is defective with an error code, or could it be another possible engine/sensor fault before I spend money?
