MKIV P1163/P1354 ECU Pin has no continuity

CopperJoy

Member
Joined
Dec 2, 2019
Location
Sedona, AZ
TDI
1999.5 VW GOLF TDI (ALH)
Recently I did an engine rebuild/replaced head gasket on a 1999.5 VW Golf TDI (ALH) 1.9L I am not able to start the car as I am getting CEL Codes P1163/P1354. I also had P1563 (Fuel Quantity Adjuster Lower Limit Reached) which has cleared. I have been doing research and reading a lot of the TDIClub forums. I took voltage reading on the Injection Pump 10-Pin wiring harness for all 10 pins and I have no continuity on pin 4 of the plug which runs to the ECU. All other 9 pins have continuity. Pin 4 is a Brown/Blue wire for the Piston Movement & Fuel Temperature Sender per the wiring diagram in my Chilton Repair Manual. The wiring diagram shows that the Brown/Blue Pin 4 wire goes to the ECU as T121/103. I've traced the wire to the ECU which is actually pin out 78. I've tested the continuity of pin 78 (in smaller wiring plug on right side of ECU) and I get NO CONTINUITY. I've replaced Relay 109, checked Engine Management Fuses F32,F34,F43, checked metal fuses and continuity on the Battery Fuse Holder. My Battery is not fully charged and I have to jump it to try to start it and testing continuity while its connected to jumper cables. I already replaced the Electronic Throttle Assembly for the Injection Pump thinking that I originally had an issue there. Car started and ran fine before I did the rebuild. At this point I am baffled.

Is there something that I am missing here or is it possible that my ECU has been compromised?

My Injection/Crank/Cam timing is all spot on. Fuel Filter/Injection Pump/Injector lines are primed.

P1163/P1354 are both Short to B+/Open Circuit. Just not sure what wires to check.

Thanks, it's been quite a headache.
 
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BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
This might help
For build date before May 1999.
The 2 codes are both for wires in that 10-pin IP connect. One is fuel temp (G81) which is pin 4, the other is modulating piston (G149) pins 1, 2 & 3.
Those wires run under the battery near the starter, one place to look for corruption. Could also be one of the sensors themselves. But the wire itself should show continuity. I see it connected to pin 76 at the ECU.
 

CopperJoy

Member
Joined
Dec 2, 2019
Location
Sedona, AZ
TDI
1999.5 VW GOLF TDI (ALH)
This might help
For build date before May 1999.
The 2 codes are both for wires in that 10-pin IP connect. One is fuel temp (G81) which is pin 4, the other is modulating piston (G149) pins 1, 2 & 3.
Those wires run under the battery near the starter, one place to look for corruption. Could also be one of the sensors themselves. But the wire itself should show continuity. I see it connected to pin 76 at the ECU.

I've already replaced the Fuel Injection Pump Electronic Throttle Assembly. For the Fuel Injection Quantity Adjuster resistance between Terminals 1 and 2, 2 and 3, 5 and 6 on the IP connector (IP side) and they are all in range. For the Fuel Temperature Sensor I have tested for resistance between Terminals 4 and 7 and I'm getting a reading of 3.0k ohms which is above the specified range of 1.5-2.0 ohms. I have tested for resistance of the Brown/Blue wire from IP connector Pin 4 to ECU connector Pin 78 and am getting a reading.

I am not getting a voltage reading on ECU Terminal 78 nor on IP connector Pin 4.

Below are some images of the wiring diagram and for testing resistance on Fuel Temp Sensor and Fuel Quantity Adjuster.

















 
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BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
What's your build date? The wire diagram I linked shows pin 4 getting a signal thru the fuel temp (diagram 4/7). The signal would come from ECU53, thru pin 7, thru the sensor and back to ECU76 (via pin 4). This would tell the brain what the temp is.
 

Matt-98AHU

Loose Nut Behind the Wheel Vendor
Joined
Apr 23, 2006
Location
Gresham, OR
TDI
2001 Golf TDI, 2005 Passat wagon, 2004 Touareg V10.
99.5s should not have a 121 pin ECU. They're 80 pin. 2000s and newer should be 121 pin.

With that said, here's what my VW diagram says for a 99.5:

T10f/1 goes to pin T80/56 at ECU
T10F/2 to T80/57
T10F/3 to T80/64
T10F/4 to T80/76
T10F/5 to S232 fuse, switched power from relay 109/j317
T10F/6 splices into the F25 connection, which goes to T80/56, 59 and 80, you will want to check for continuity to all 3 pins.
T10F/7 to T80/53
T10F/8 to T80/77
T10F/9 to T80/79
T10F/10 to fuse S234, once again powered by relay 109/J317 along with a host of other items.

T10F/4 and 7 are for the fuel temp sensor and nothing else. So if you have an open circuit between T10F/4 and T80/76, that would explain a code for fuel temp sensor open circuit/implausible signal/P1163.

The P1354 and P1563 are both relating to the quantity adjuster's operation.

T10f/1, 2 and 3 are all for the modulating displacement sensor.

T10F/6 is the ECU switched ground control to the quantity adjuster via 3 pins mentioned. I can only assume that the current draw of the large electromagnet that is the quantity adjuster required that 3 separate pins from the ECU take this load rather than just one. So again, check continuity to all 3 pins as described above.

T10F/5 should have 12V with key on, this is the power feed to the quantity adjuster.

If you can confirm all of that is OK, then time to use a proper VAG scan tool to see what's going on. Every time you turn the key on, before starting the vehicle, the ECU does a full sweep of the quantity adjuster, min to max position. The raw voltage readings of this plausibility check/sweep is stored in measured value block 19. Field 1 is the min reading, field 2 is the max reading of the position sensor. VCDS has a built in guide that tells you the acceptable voltage range of both positions. The information may also be contained in the Bentley manual and is definitely in the VW repair info I have from ERWIN.

The acceptable ranges in measuring block 19:

Field 1: 0.500V to 0.970V
Field 2: 4.150V to 4.740V

If one or both of those are out of spec for whatever reason, you will get a code for quantity adjuster upper or lower limit not reached or exceeded depending on what happens. Most of the time, it's a bad quantity adjuster, or as you put it "electronic throttle assembly."

As ever, the right scan tool and having enough know how on where to look (or have know-it-alls like me help steer you the right direction) to evaluate what's going on are indispensable. The right scan tool being something that can do much more than just retrieve and clear codes, like Ross-Tech's VCDS.
 
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CopperJoy

Member
Joined
Dec 2, 2019
Location
Sedona, AZ
TDI
1999.5 VW GOLF TDI (ALH)
What's your build date? The wire diagram I linked shows pin 4 getting a signal thru the fuel temp (diagram 4/7). The signal would come from ECU53, thru pin 7, thru the sensor and back to ECU76 (via pin 4). This would tell the brain what the temp is.

Build date is 11/1998, Thanks for the diagram. Seems more accurate than the Chilton diagram considering that I have the 80 Pin ECU. I'll double check my ECU pins in the morning but I have Pin 4 going to ECU78 last I checked. The pin numbers are on the black plastic of the ECU pin connector port. ECU76 is the top left pin on the smaller wiring connector and there is NOT a wire there so that's a bit confusing. I'll check ECU53/Wire 7 for continuity as well as the others. I suppose I should check the F25 wire connection harness from Pin 6 to ECU66/59/80. I guess I'm confused about Pin 5 from QA N146 going to 31 (in rectangle box)?

Really appreciate the info!! Thank you!
 

Matt-98AHU

Loose Nut Behind the Wheel Vendor
Joined
Apr 23, 2006
Location
Gresham, OR
TDI
2001 Golf TDI, 2005 Passat wagon, 2004 Touareg V10.
Build date is 11/1998, Thanks for the diagram. Seems more accurate than the Chilton diagram considering that I have the 80 Pin ECU. I'll double check my ECU pins in the morning but I have Pin 4 going to ECU78 last I checked. The pin numbers are on the black plastic of the ECU pin connector port. ECU76 is the top left pin on the smaller wiring connector and there is NOT a wire there so that's a bit confusing. I'll check ECU53/Wire 7 for continuity as well as the others. I suppose I should check the F25 wire connection harness from Pin 6 to ECU66/59/80. I guess I'm confused about Pin 5 from QA N146 going to 31 (in rectangle box)?
Really appreciate the info!! Thank you!
The 31 in the box is a continuation track. Look at the number that is inline with it below (80).

Scroll up a couple pages until you find 31 on the bottom line, go up on that "track" until you find a wire that terminates with a box labeled 80, indicating it's a continuation of the wire from track 80.

There you'll find it splices into the B168 connection, which ultimately traces back to fuse S232, which can be traced back to being powered by the J317/relay 109.

Now you know how to track wires on a DIN style diagram :D
 

BobnOH

not-a-mechanic
Joined
May 29, 2004
Location
central Ohio
TDI
New Beetle 2003 manual
Build date is 11/1998,.............................!
So that wire diagram I linked is the correct one. IIRC ECU78 is for needle lift sensor, 2 pin connector at the #3 injector.
Besides chilton being wrong (no surprise), you may have some other tomfoolery going on. Possible the car was converted from auto to manual?
Fuel temp should not keep the car from starting, but IQ thing might.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
Keep in mind, the Chilton (I would not trust that any further than I could throw it) may not only be flat out wrong, but for a 1999 model year car, may be confused with the earlier TDI engine, which is completely different.

VAG specific scan tool, and the proper DIN type track wiring diagram, and you will be better able to find the source of your problem(s).

The QA in the pump may be stuck from sitting. It happens if the fuel was drained out during the work performed, which happens because the delivery pipes would have been off, so....
 

CopperJoy

Member
Joined
Dec 2, 2019
Location
Sedona, AZ
TDI
1999.5 VW GOLF TDI (ALH)
So that wire diagram I linked is the correct one. IIRC ECU78 is for needle lift sensor, 2 pin connector at the #3 injector.
Besides chilton being wrong (no surprise), you may have some other tomfoolery going on. Possible the car was converted from auto to manual?
Fuel temp should not keep the car from starting, but IQ thing might.

I was mistaken. ECU 76 is Pin/Wire 4 Brown/Blue.

VIN lookup checks out to manual transmission.
 

CopperJoy

Member
Joined
Dec 2, 2019
Location
Sedona, AZ
TDI
1999.5 VW GOLF TDI (ALH)
Well everything seems to be good as far as all the electrical connections getting continuity everywhere. Relay 180 and 109 are new. Now I'm not getting any CEL codes. Still can not get it started. Maybe too much air in my fuel lines still? Already primed the fuel filter/injection pump/injector lines. No previous or current error codes for injectors. Will have to give a try cracking injector lines and turning over/closing lines to make sure I get the last bit of air out. Can't imagine the IP would not be creating enough pressure or that the IP is bad. Everything was working good before the engine rebuild. OBD2 is communicating with ECU. Hmm....
 
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