P161A and keeps comping back

Jakub

Veteran Member
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Mar 30, 2014
Location
Chatsworth
TDI
2000 Vw golf tdi
2006 Vw Jetta tdi automatic Brm

I have changed the glow plugs and glow plug harness and I still keep getting these codes, any ideas please

P161A open circuit
P161B
P161C
P161D
 

Jakub

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Location
Chatsworth
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2000 Vw golf tdi
Vagcom
What number is the glow plug relay?
The glow plug light does come on though
 

oilhammer

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outside St Louis, MO
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There are just too many to list....
The J179 Automatic Glow Time Control Module is located under the underhood fuse box. You need to remove the battery to get at it, it slides out. Usually has a '461' printed on top of it, but it is the only relay there.
 

Jakub

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Location
Chatsworth
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2000 Vw golf tdi
So under the battery and under the battery tray as well ? Can I clean it or is it usually bad ?
I do see the fuse box that’s next to the battery but that’s not the right one right?
 

Jakub

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2000 Vw golf tdi
Ok I found it, I’m pulling it from my other car and swapping it to see if it solves the codes.
 

Jakub

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Location
Chatsworth
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2000 Vw golf tdi
Ok so I swapped the glow plug relays and no luck the codes come back.
One more thing I noticed is when I come to a stop my rpm is randomly elevated to 1,000 rpm can that be correlated ?
 

oilhammer

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There are just too many to list....
Do a voltage drop check on the circuits. Especially at the connector near the headlamp for the glow harness.
 

Jakub

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Location
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2000 Vw golf tdi
Is there a resistance I’m looking for ?
Is there a engine sensor that tells the glow plugs when to activate ?
 

oilhammer

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outside St Louis, MO
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Voltage drop test. Not resistance. Resistance (like, with an ohm meter) will tell you if the circuit is "complete", but not if it is "good". You need to put a load on the circuit to mimic the plug and while doing so check for a voltage drop from one end to the other.

Start by checking the condition of the connector, like I said, near the headlamp. The four wires will be the same colors as the one at the connector bridge on the engine. Black with a color tracer.

The engine uses coolant temp to control the plugs, that is not the issue here.

And I assume you have checked the Glow fuse link?
 
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Jakub

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2000 Vw golf tdi
Just so I’m clear which is the fuse link?
I have heckled the relay
Checked glow plugs
Checked glow plug harness as well
The glow plug light in the cluster
Comes on a turns off
 

oilhammer

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outside St Louis, MO
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One of the fuse links attached to the bus bar at the front of the underhood fuse box. I forget which one, but it is probably a 40A or 50A fuse link.

Have you checked (third time I have asked this) the glow harness CONNECTOR near the headlight?

It may look like this:



Or like this:



Depending on build date.

This is where the glow plug bridge (the plastic thing that actually snaps on to the plugs) is connected through the engine harness and attaches to the car's wiring, and then in turn goes to the glow control relay under the fuse box. You need to verify this connection is good, and all four wires (again, look at the wires on the harness for the colors... they are all black, with four different colored tracers) are good. This will at least split your potential wire problem areas in two... good/not good from the connector to the bridge, good/not good from the connector to the relay plug.

Check the fuse. Check the wiring to and from this plug. Don't post again until you have checked these things.
 
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Jakub

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Chatsworth
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2000 Vw golf tdi
All the fuses are getting power
There is continunity going from electrical plug to glow plugs
The plug end that is part of the cars wiring has readings as follows
0.12volts with Car off .. when I turn the key to on position without turning on Car the voltage goes to 0.00 to 0.01 it fluctuates
So that’s where I’m at now
 

Jakub

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2000 Vw golf tdi
So those are my readings. I just feel no voltage is being sent to the glow plugs , but also, the idle runs at 1,000 rpm when parked or standing at a light as if the car believe the engine is cold and needs to heat up.
 

oilhammer

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What does the ECU think the coolant temp value is?

So you have constant battery power on the big lug into the glow relay at all times, correct?
 

Jakub

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2000 Vw golf tdi
Yes constant battery power

What value in the vagcom show I look up to find out?
On my cluster it’s reg operating temp of 190
 

oilhammer

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Scroll through the Engine's data blocks and there will be one (or more) that show coolant temp. I would check it against the other temp sensor values when the engine is cold before you start it.
 

Jakub

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2000 Vw golf tdi
Question just bec I looked at some measuring blocks my alternator is charging 11.23-11.70v could low charging be causing my issues with other electrical stuff
 

Jakub

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Location
Chatsworth
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2000 Vw golf tdi
So I changed the alternator, went thru all my grounds by disconnecting and cleaning them and the codes have not re appeared and no high idle

Thanks
 

oilhammer

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Location
outside St Louis, MO
TDI
There are just too many to list....
Thanks for the follow up. Yes, everything goes out the window with low voltage. Glad you got it fixed. I would imagine other modules in the car may have low voltage DTCs stored, too. Especially the SRS.
 
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