Ubique
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- East Midlands
I thought I'd start a repository for irregular updates of notable jobs I'm involved in - I wanted to call it 'Sh!ts & Giggles in a JLR workshop' but 'GSOH' isn't an acronym compatible with forum moderation...
Firstly, I work for an independent JLR workshop, so warranty policies & procedures (WPaP) will not always be followed, We do have & use fully licenced versions of SDD & Topix Cloud, but often use Topdon aftermarket diagnostics as they're quicker to get an initial DTC scan from, and easier to get live values on screen to provide data for diagnosis.
It's a small workshop - only four tech's, three of which have been trained to MT level in dealerships.
So, to start off!
2023 Defender with a 'restricted performance' message on dash - no EML, drives OK, engine is DI6 (Ingenium straight six diesel) with three DTC's on second read
Water in fuel sensor, short to ground
Active engine mount solenoid, short to ground
Piston cooling control solenoid, short to ground
The first thing to note is that 'short to ground' shouldn't be taken literally (or actually!), it often just means 'loss of power supply to component' - in much the same way that 'short to positive' often just means open circuit in a positive switched or monitored circuit. - note that many automotive actuators or 12VDC sensors have switched or monitored ground terminals, with the 12VDC provided via a relay controlled fused circuit.
A quick check of the wiring diagram / current flow diagram indicates all three components are powered from the same 10A fuse with a splice joint in the harness, so it's no surprise they all have a 'short to ground' DTC after checking the fuse link which had blown - there was no blackening of the fuse around where it'd blown, indicating it was an overload, not a direct short.
Replaced the fuse and turned on the ignition - it took ~5 seconds for the fuse to rupture, but there was a slight whiff of 'expensive' coming from the NSF of the engine, the only component on that circuit near there is the oil control solenoid (Piston cooling control solenoid), so time to take a look..
It's a MHEV so a forced shutdown is required, as the starter-alternator needs to be removed, after removing the belt tensioner, lots of coolant pipes (and draining the system) to get to this....
The oil control solenoid is behind a coolant hose & manifold...
Looks like it's had a bit of an 'eruption'!
Yep, all that molten plastic is where the 'expensive smoke' came from, resistance measurement of 8 Ohms to ground (should be >1MOhm) confirms internal defect, unfortunately not the same as the 4 cylinder ones we keep in stock and on backorder with no ETA....
So put it back together enough to move around the yard and wait on parts. So far, just under two hours including making mobile again - there's worse jobs!
Firstly, I work for an independent JLR workshop, so warranty policies & procedures (WPaP) will not always be followed, We do have & use fully licenced versions of SDD & Topix Cloud, but often use Topdon aftermarket diagnostics as they're quicker to get an initial DTC scan from, and easier to get live values on screen to provide data for diagnosis.
It's a small workshop - only four tech's, three of which have been trained to MT level in dealerships.
So, to start off!
2023 Defender with a 'restricted performance' message on dash - no EML, drives OK, engine is DI6 (Ingenium straight six diesel) with three DTC's on second read
Water in fuel sensor, short to ground
Active engine mount solenoid, short to ground
Piston cooling control solenoid, short to ground
The first thing to note is that 'short to ground' shouldn't be taken literally (or actually!), it often just means 'loss of power supply to component' - in much the same way that 'short to positive' often just means open circuit in a positive switched or monitored circuit. - note that many automotive actuators or 12VDC sensors have switched or monitored ground terminals, with the 12VDC provided via a relay controlled fused circuit.
A quick check of the wiring diagram / current flow diagram indicates all three components are powered from the same 10A fuse with a splice joint in the harness, so it's no surprise they all have a 'short to ground' DTC after checking the fuse link which had blown - there was no blackening of the fuse around where it'd blown, indicating it was an overload, not a direct short.
Replaced the fuse and turned on the ignition - it took ~5 seconds for the fuse to rupture, but there was a slight whiff of 'expensive' coming from the NSF of the engine, the only component on that circuit near there is the oil control solenoid (Piston cooling control solenoid), so time to take a look..
It's a MHEV so a forced shutdown is required, as the starter-alternator needs to be removed, after removing the belt tensioner, lots of coolant pipes (and draining the system) to get to this....
The oil control solenoid is behind a coolant hose & manifold...
Looks like it's had a bit of an 'eruption'!
Yep, all that molten plastic is where the 'expensive smoke' came from, resistance measurement of 8 Ohms to ground (should be >1MOhm) confirms internal defect, unfortunately not the same as the 4 cylinder ones we keep in stock and on backorder with no ETA....
So put it back together enough to move around the yard and wait on parts. So far, just under two hours including making mobile again - there's worse jobs!
