Nissan Primera P12 1.8 petrol - starter disabled |
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P12QG18DE
NPOC Guest Joined: 24 Mar 2022 Online Status: Points: 8 |
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Posted: 24 Mar 2022 at 9:03am |
2003 hatchback with QG18DE engine and 5-speed manual transmission. Starter motor not cranking. Two mile trip into local village and back vehicle started fine both times. Half-hour later at home refuses to start with no indications as to what is wrong. Engine simply does not crank. No previous issues. When turning the key form ON to START the central display blanks then resumes when key returns to ON - cannot recall whether this is normal behaviour so reporting it here in case it is a clue! Initially suspected NATS although the dash warning light flashes normally, and at ignition on, shows for a few seconds then stays off. Tried the spare key. No fault codes reported via ODB2, or the Smart Entry module, or ECM module. Fed the solenoid with 12V directly and the starter motor engages and cranks. Battery charge was slightly low so gave it a full charge. Read other topics here about possible problems with corrosion / resistance in the primary grounding strap from battery to chassis and gearbox. Removed, cleaned, tested. Found information about the gearbox neutral signal sensor and tested it Located on the lower rear of the gearbox, facing the left wheel. With a continuity test it reports closed circuit when gearbox in neutral and open circuit when in gear. Traced the signal from the right-most terminal of the connector (black wire - when looking into the in-line connector on the wire, with the locking clip at top) and found a perfect continuity (0.3 ohms) to the starter solenoid activation terminal. So far the circuit diagrams I've found seem to relate to only diesel engines (LD and F9Q engines) and mention the Smart Entry Control unit that, for automatic gearboxes, has the Park/Neutral detection and starter on pins 58+59 but not found anything about the manual gearbox's neutral sensor and where it connects to. Still trying to locate the info on this QG18DE + 5 speed manual gearbox circuits. Some signs of mice chewing various foam insulation but not seen any damaged wires.
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P12QG18DE
NPOC Guest Joined: 24 Mar 2022 Online Status: Points: 8 |
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Quick update after having downloading the service manual and found the info I was lacking. SC-START-01 on page SC-24 shows the /M/T (manual transmission) starting procedure and the circuit passing through the SEC (Smart Entry Control unit) pins 58 and 59. It does not show any linkage to the gearbox's "PNP Switch" referred to on page MT-14. So I'm now hunting for it in the circuit diagrams to figure out how it gets involved - since SC-24 shows a 'straight through' circuit from ignition switch via SEC to starter solenoid.
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P12QG18DE
NPOC Guest Joined: 24 Mar 2022 Online Status: Points: 8 |
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Update 2: Info on the Park/Neutral Position (PNP) switch is found at EC-1913 onwards. It connects to the ECM on connector F114, pin E13. Next job is to find the ECM and test continuity from sensor to pin! Any other ideas welcome since I'm just being methodical right now, with no other clues. P.S. I notice the Consult diagnostics is supposed to be able to read the data from this sensor. I'll double-check with my iCar Japan diagnostic if a PNP is mentioned in the ECM module. I skipped through the 120+ options last night but the names are cryptic and I didn't know precisely what to look for.
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P12QG18DE
NPOC Guest Joined: 24 Mar 2022 Online Status: Points: 8 |
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Update 3: Using my iCarSoft diagnostic tool I found the Park/Neutral Position monitor and it correctly reports gearbox in neutral. So now need some other avenue to explore!
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roy.2
NPOC Elite Member Joined: 23 Jan 2010 Location: Nr Bourne Lincs Online Status: Points: 3976 |
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Hi. Welcome to NPOC. You are persistant if nothing else.
I would still suspect a bad earth lead.
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Roy
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timeshock!
NPOC Guest Joined: 29 Jan 2006 Location: Newcastle Online Status: Points: 14483 |
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Hi and welcome to the forum
This sound like a broken earth lead
Check the
battery earth leads to the chassis and transmission particularly the latter
making sure they have good connection and no breaks |
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P12QG18DE
NPOC Guest Joined: 24 Mar 2022 Online Status: Points: 8 |
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I did a further ground test using a jump lead between battery and an engine brace mounting adjacent to the starter motor, to over-ride any fault in the primary ground strap. No difference. I then noticed that, when ignition switch is moved to ON, the NATS Security Indicator lamp does NOT flash. It flashes on the normal cycle (0.2s on, 2.4s off) with key withdrawn. Looking at the NATS related diagnostic tasks at page BL-192 it suggests PROCEDURE 8 on page BL-200 and/or PROCEDURE 9 on page BL-201 when "Security ind. dose [sic] not blink just after ignition switch is turned to ON ...". Here's where it gets confusing. PROCEDURE 8 step 3 "Check Interface Circuit"
But where the heck is this "dongle unit" and what does it look like? The manual states that on European right-hand drive models a dongle unit is used alongside the IMMU for "additional security" but there's no component reference. According to PG-39 M93 appears to be in the left side A-post (grid C1) but could also be the other side of the engine/wing bulkhead. If in, or at base, of the A-post it looks like the entire front console would have to be removed to get to it. Anyone familiar with this and know of easier approaches to perform the same diagnostic steps described in PROCEDURE 8 and 9 ?
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P12QG18DE
NPOC Guest Joined: 24 Mar 2022 Online Status: Points: 8 |
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Resolved finally! NATS was a red herring - I realised - as the starter circuit diagram makes clear - that NATS doesn't get involved in the starter at all. It simply prevents ignition and fuel pump. So, I went back to SC-24 and traced the circuit, sticking a safety-pin into the SEC (IMMU) pins 58 (input) and then 59 (output) and confirmed there's 12V when ignition switch is in START. I then removed the passenger glove-box to access the M78 (on main loom) <> F106 (to engine bay) 2-pin grey connector and found that spade terminal (pin 1) of M78 had physically snapped - the wire was hanging free. The spade connector had broken at the shoulder so the clamp and wire came out of the plastic receptacle whilst the spade itself remained in place. I removed the remaining spade part and cut the shoulder off the wire then crimped a standard car spade connector on the wire, cut away the plastic shroud to allow it to slip into the M78 receptacle and since it wouldn't lock in place like the original wrapped the wires with insulation tape to hold it. I have a couple of photos: |
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timeshock!
NPOC Guest Joined: 29 Jan 2006 Location: Newcastle Online Status: Points: 14483 |
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Well done with your perseverance, pleased you got it sorted
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roy.2
NPOC Elite Member Joined: 23 Jan 2010 Location: Nr Bourne Lincs Online Status: Points: 3976 |
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Very well done on finding that. Great you got it sorted.
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Roy
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