Over but wont start

Tiny
BUCKAROO_BONZAI
  • MEMBER
  • 2002 VOLKSWAGEN BEETLE
  • 2.0L
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 40,500 MILES
AVH engine & Auto Trans (44,200 miles).
Wife's car- died in midst of driving.
Started with simple tests in parking lot (pre-tow):
tested with starter fluid direct to intake - cranks no start.
No spark via inline tester.
initial error codes = P0725, P1780, P1850 found with an Actron CP9850A OBDII.
Codes reset to attempt restart. Still no start, no codes set when cranking.
EPC and Check Engine Lights remain on (constant). Other lights cycle per spec.
All other functions (lights, wipers, heat/AC, radio (stock), seats, trunk lock, door locks, etc) appear to function normally.
Lights and such activate with door opening - seeming to clear any micro-switch issues.

Got it towed back to house.
replaced with a new battery - old battery was the original & tested on margin - 12 years old and starting to go.
battery case top fuses all intact - continuity good (see relay power test below).
All battery top fuses and cables good, clean and test at 12V.
attempted reset by pos & neg battery cable joined for 30+ secs - no change.
- based on the P0725 code and reading is this forum and elsewhere -replaced crank sensor - new
(resistance tests[1-2, 2-3, 1-3] new sensor @0/700/0 ohms; old sensor also tested @0/700/0).
Tach "bumps" (sub 500) when cranking.

replaced fuel filter (just in case)
Fuel pump cycles with door opening (at low pressure) and at key power on (as pressure dictates) and can hear relay contacting on/off during those intervals
- seems to indicate that inside relay 409 functioning. I have not tested the leads on the pump as result and per below tests indicating good pump.
Fuel level correctly indicates with key on.

? However - note fuse readings below (possible anomolies)?

engine compartment relay 428/grey - ECM -
tested 428 relay sockets - key off / on:
85- 2.16v / 0.4v?
86- 12v / 12v
30- 12v / 12v
87- 0v / 0v
85-86- key on = 11.62v
simple activation test- 12v jump 85/86- closes 30/87 contact
no corrosion on relay pins or in sockets- very clean (true for all relays)

Interior relay power terminals all test 12v per spec:
75x- 0/12 (key off/key on)
30.1- 12/12
30.2- 12/12
30a- 12/12
87F- 0/0


Fuses (continuity test for all [1-44] - good): power tests key off / key on / crank
5 - 0/12/did not test crank
7 - 0/12/did not test crank
**10 - test sequence: 0 with no key, 0 key in off, 12 key on, 12 crank, 12 key off, 0 no key- put key in off = 0, 12 key on, etc?** Is this an anomoly?
11 - 0/12/did not test crank
28 - 0/0/0
29 - 0/12/did not test crank
32 - 0/0/0
34 - 0/0/0
43 - 0/0/0

So it appears to me that a symptom of the problem(s):

Sympton #1-
fuse#10 test- no power with key out, or with key first put in; only 12v power after key turn.
This seems odd to me since - the diagrams I found (Bentley and Haynes) seem to indicate that this circuit is direct power from the battery.
Correct?
Question - with no key in the ignition - should fuse#10 see 12v (always hot)?
Or does fuse 10 only see power when the key has been inserted (key sense)? --Diagrams don't show fuse#10 going through ign switch.
What role does the power feed through fuse 10 to the ECM play?
Must the ECM always (even without key on) have a power feed?

Symptom #2-
fuses 28, 32, 43 no receiving power -
I jumped 2-8 terminals at Relay409 - the fuel pump run continuously and I have power at 28, 32& 43.
Also - when pump cycles- and I can catch it- I do have power at 28, 32& 43- until (relay opens) and pumps shuts off.
This seems to indicate a good ECM functioning and good Relay409. Right?
This seems to point to a problem at the ignition switch end giving signal to Relay409.

Symptom #3-
Fuse 34- seems to be the PCV heating element. Correct?
This might throw a code via the ECM - but this should not cause a no start condition.
Correct?


I only have an Actron code reader - no VW specific tool.
My goal is to rule out all hardware and wiring items - prior to messing with the dealer & ECM. (There are no VW mech's in my town- 30 mile tow, etc.)
Periodic fuel pump prime -seems to indicate that ECM is getting some power & fullfilling function.

Per the above- IF- fuse#10 goes through the ignition switch -and- if T15(black wire to Relay409) from ignition switch is bad- this would explain 2 of 3 symptoms.
Seeming to indicate ignition switch replacement.

thanks for any help.
IF we keep the vehicle will likely get clone cable and VSDS-light(registered)--- but only IF.
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Friday, May 30th, 2014 AT 8:57 AM

39 Replies

Tiny
EXOVCDS
  • CERTIFIED MECHANIC
Relay 428 should have have power at 87 when the key is turned on. The relay is controlled by 85 & 86. Battery power all the time at 30 should feed 87 when the relay is closed.

This guide should help

https://www.2carpros.com/articles/car-cranks-but-wont-start

Thomas
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Thursday, June 5th, 2014 AT 4:53 PM
Tiny
TCOB
  • MEMBER
Thank you for this post I followed the guide and found out my fuel pump was bad cost me $213.00 all fixed! I love this site.
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+1
Saturday, August 31st, 2019 AT 2:21 PM
Tiny
CP123
  • MEMBER
  • 2002 VOLKSWAGEN BEETLE
  • 1.8L
  • 4 CYL
  • TURBO
  • 2WD
  • MANUAL
  • 10,500 MILES
Car died on freeway almost just like the key was turned off now it wot start there's no spark change fuel pump changed crankshaft sensor and still no spark. When scanned no codes come up just like it won't read it
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Saturday, August 31st, 2019 AT 2:21 PM (Merged)
Tiny
SATURNTECH9
  • CERTIFIED MECHANIC
So are you using a basic code reader?Also does it say no codes on the code reader or does it even link up to the car?
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Saturday, August 31st, 2019 AT 2:21 PM (Merged)
Tiny
CP123
  • MEMBER
I plugged it in and got nothing. I. Know the scanner works because my car has read codes before. I was told it maybe my ecu so I checked the pins on the ecu and got no readins on small and large cinnectors. Also when the key Iis, in the ignition and I turn it the check engine light comes on for a couple of seconds then fades out. This is without turning the engine over. I found that odd. I have been without a car fior five weeks now. No way to get to work so I lost my job. Ouch! Need car running for oily can get back to work. Please, please help. Thank you
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Saturday, August 31st, 2019 AT 2:21 PM (Merged)
Tiny
SATURNTECH9
  • CERTIFIED MECHANIC
Have you checked all the fuses yet?
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Saturday, August 31st, 2019 AT 2:21 PM (Merged)
Tiny
CP123
  • MEMBER
Yes I have checked all fuses and they are good.
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Saturday, August 31st, 2019 AT 2:21 PM (Merged)
Tiny
SATURNTECH9
  • CERTIFIED MECHANIC
So the code reader wont even power on off the obd2 connector?If not thats the first thing that must be fixed. Its fuse number 12 its a 7.5 amp fuse all it powers is power to that obd2 connector make sure there is power to both sides of that fuse.
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Saturday, August 31st, 2019 AT 2:21 PM (Merged)
Tiny
CP123
  • MEMBER
I just checked the number 12 fuse the fuse is good all my fuses are good it just won't read codes might be electrical or the computer. Were gonna have to diagnose the vehicle without a scanner
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Saturday, August 31st, 2019 AT 2:21 PM (Merged)
Tiny
TPANNO
  • MEMBER
  • 2001 VOLKSWAGEN BEETLE
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 95,000 MILES
Car was running. Had to change water pump. Trouble getting timing belt right. Car would start right up then die in 15 min. Then changed the belt again. Car starts runs but needs timing adj. Finally car will not start at all. Get P0322. No spark. Did LED light on coil connector on 2 and 3 no blinking light while tturning over starter. Book says look for broken wire to coil? No broken wire visible. Terms 1 and 4 and 1 and 2 have 12 volts per book.
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Saturday, August 31st, 2019 AT 2:21 PM (Merged)
Tiny
MERLIN2021
  • CERTIFIED MECHANIC
First let me say I am NOT a VW mech, but have found info on your code,
Engine Speed (RPM) Sensor G28, checking NOTE: Use only gold-plated terminals when servicing terminals in the electrical harness connector of the Engine Speed (RPM) Sensor G28. " Special tools, testers and auxiliary items required Multimeter. " Wiring diagram. " Test requirements Fig. 76: Identifying Main Fuse Panel Courtesy of VOLKSWAGEN UNITED STATES, INC. The Motronic Engine Control Module (ECM) J220 fuses OK. " Battery voltage at least 12.5 volts. " All electrical consumers such as, lights and rear window defroster, switched off. " Vehicles with automatic transmission, shift selector lever into position "P" or "N". " A/C switched off. " Ground (GND) connections between engine/transmission/chassis OK. " Ignition switched off. " Test procedure Perform a preliminary check to verify the customers complaint. Refer to ’ Generic Scan Tool (GST) Manual Contents " Start diagnosis Function The Engine Speed (RPM) Sensor G28 detects RPM and reference marks. Without an engine speed signal, the engine will not start. If the engine speed signal fails while the engine is running, the engine will stop immediately. Function test Connect the scan tool. " Switch the ignition on. " Using the scan tool, check the engine speed: " End diagnosis and switch ignition off. " If the specified value was not obtained: Checking internal resistance Fig. 77: Identifying Engine Speed Sensor G28 Electrical Harness Connector Courtesy of VOLKSWAGEN UNITED STATES, INC. Disconnect the Engine Speed (RPM) Sensor G28 electrical harness connector - arrow -. " Fig. 78: Checking Engine Speed Sensor G28 Terminals 2 To 3 For Resistance Courtesy of VOLKSWAGEN UNITED STATES, INC. Using a multimeter, check the Engine Speed (RPM) Sensor G28 terminals - 2 to 3 - for resistance. " Specified value: 480 to 1000 © (at approx. 20 °C) Check Engine Speed (RPM) Sensor G28 terminals 1 to 2 and 1 to 3 for short circuits. " Specified value: (infinity) If any of the specified values are not obtained: Replace the Engine Speed (RPM) Sensor G28. Refer to 13 - ENGINE - CRANKSHAFT, CYLINDER BLOCK " If the specified values are obtained: Checking wiring If the manufacturers test box is being used, perform the following step. Install the Adapter Cable (121-pin) VAG1598/31. Refer to 24 - MULTIPORT FUEL INJECTION (MFI). " If the manufacturers test box is not being used, perform the following step. Remove the Motronic Engine Control Module (ECM) J220. Refer to ’ Motronic Engine Control Module (ECM) J220, Replacing. " Fig. 79: Identifying 3-Pin Harness Connector Terminals Courtesy of VOLKSWAGEN UNITED STATES, INC. Using a Multimeter, check the Engine Speed (RPM) Sensor G28 electrical harness connector T3 terminals to the Motronic Engine Control Module (ECM) J220 electrical harness connector T121 terminals for an open circuit. " Specified value: 1.5 © Max. If the specification was not obtained: Check the wiring for a short circuit to each other, Battery (+), or Ground (GND). " Check the electrical harness connector for damage, corrosion, loose or broken terminals. " If necessary, Repair the faulty wiring connection. " If no malfunction is detected in the wiring: Remove the Engine Speed (RPM) Sensor G28 and check the sensor wheel for proper seating, damage and run-out. Refer to 13 - ENGINE - CRANKSHAFT, CYLINDER BLOCK. Replace if damaged. " If the sensor wheel is OK: Erase the DTC memory. Refer to ’ Diagnostic Mode 04: Reset/delete diagnostic data. " Perform a road test to verify Repair. " If the DTC does not return: Repair complete, Generate readiness code. Refer to ’ Readiness Code. End diagnosis. " If the DTC does return and no malfunction is detected in the wiring and the voltage supply was OK: Replace the Motronic Engine Control Module (ECM) J220. Refer to ’ Motronic Engine Control Module (ECM) J220, Replacing. " Assembly is performed in the reverse of the removal. " Final procedures After the Repair work, the following work steps must be performed in the following sequence: Check the DTC memory. 1. If necessary, erase the DTC memory. Refer to Diagnostic Mode 04: Reset/delete diagnostic data. 2. If the DTC memory was erased, generate readiness code. Refer to Readiness Code. 3. End of diagnosis.
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Saturday, August 31st, 2019 AT 2:22 PM (Merged)
Tiny
SATURNTECH9
  • CERTIFIED MECHANIC
So is there power on both sides of the number 12 fuse?Also does the code reader power up off the obd2 connector? Is there power at the number 16 pin of the obd2 connector? These are all important questions to see if the computer might not be working. Iam not there to check these thing's myself and iam really trying to help you.
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Saturday, August 31st, 2019 AT 2:22 PM (Merged)
Tiny
CP123
  • MEMBER
Hi again sorry its taking so long to get back to you and I checked both things that you told me to check there is power to both sides of the number 12 fuse and also the number 16 pin I got a reading of 12.32
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Saturday, August 31st, 2019 AT 2:22 PM (Merged)
Tiny
CP123
  • MEMBER
I really appreciate your help. I will be so happy when I find out what's wrong with this car and get it back on the road. Thank you
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Saturday, August 31st, 2019 AT 2:22 PM (Merged)
Tiny
SATURNTECH9
  • CERTIFIED MECHANIC
So does the code reader power up off the obd2 connector?
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Saturday, August 31st, 2019 AT 2:22 PM (Merged)
Tiny
CP123
  • MEMBER
The scanner says that there is no communication. Could this maybe be due to the chip in my key or maybe s bad computer?
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Saturday, August 31st, 2019 AT 2:22 PM (Merged)
Tiny
SATURNTECH9
  • CERTIFIED MECHANIC
Even when all keys are lost on the vws and I have to code a brand new key I can still read the computers just cant start the car till I code the new key. So you could a bad power or ground to the computer. Which engine do you have?
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Saturday, August 31st, 2019 AT 2:22 PM (Merged)
Tiny
CP123
  • MEMBER
Its 1.8 turbo. What do you recommend I do next? Please help
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Saturday, August 31st, 2019 AT 2:22 PM (Merged)
Tiny
CP123
  • MEMBER
If no bad grounf is found should I try a new computer and if yes I found one on ebay with the ecact number s the one in the car. Since the numbers are the same can I get away with having it programmed by professional?
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Saturday, August 31st, 2019 AT 2:22 PM (Merged)
Tiny
SATURNTECH9
  • CERTIFIED MECHANIC
Your going to want to get the used one programmed with the correct vin calibration for your exact car etc. You have to make sure the grounds and powers to the computer are good. Have you checked the crankshaft position sensor yet?
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Saturday, August 31st, 2019 AT 2:22 PM (Merged)

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