# 99 passat won't IDLE. Please help. "OBD Code P1545"



## danandjonna (Jun 25, 2004)

Car battery went dead (perhaps unrelated). I charged the battery and It cranks but doesn't stay running unless I pump the throttle pedal or keep it reved at 2-3K RPMs. when I let off the pedal it stalls out. I scanned it with my scanner and came up with code P1545. Idle speed control...Throttle Position Sensor Perhaps? I don't want to replace it (TPS) with out input that this is my problem. Where is a good cheap place for a part like this. I wouldn't mind a used part. Suggestions/comments


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## evlgreg (Jan 6, 2000)

*Re: 99 passat won't IDLE. Please help. "OBD Code P1545" (danandjonna)*

Perhaps a fuel pressure regulator? If the seal is broken, the fuel rail cannot maintain enough pressure to send fuel through the injectors.
If you turn the key to the on position, do you hear a faint buzzing of the fuel pump as it tries to pressure the line before you start? If so, spen $40 and install a FPR.
Just a thought.


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## hugemikeyd (Aug 28, 2001)

*Re: 99 passat won't IDLE. Please help. "OBD Code P1545" (evlgreg)*

maybe your alternator is dead, hook up a multimeter to the battery while a friend starts her up, should read at least 14v


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## VWtechfromIL (Jun 25, 2004)

*Re: 99 passat won't IDLE. Please help. "OBD Code P1545" (danandjonna)*

Both of those options are very unlikely. If your battery went dead then you need to restore electrical power procedure. Which the most important step is to adapt your throttle body. The fault you show "P1545" is a fault for a bad throttle body control module. It is possible that cleaning your throttle body will help, but you most likely are looking at a new throttle body, which costs in excess of $400 plus labor. If I was you I would clean the throttle body, and see if that helps. If not, you're looking at a throttle body


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## Stroked1.8t (Jan 9, 2004)

*Re: 99 passat won't IDLE. Please help. "OBD Code P1545" (VWtechfromIL)*

you can't just buy the TPS from what my dealer tells me. it is part of the TB and must be replaced as one unit.


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## evlgreg (Jan 6, 2000)

*Re: 99 passat won't IDLE. Please help. "OBD Code P1545" (VWtechfromIL)*

I don't think a 99 Passat HAS a TB control module. Doesn't it have a cable? Mine does. Perhaps its a TB Sensor.










_Modified by evlgreg at 11:54 PM 6-25-2004_


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## I-Rocco2 (Dec 8, 2003)

*Re: 99 passat won't IDLE. Please help. "OBD Code P1545" (danandjonna)*

It says in Bentley Manual Throttle Postion Control malfunction. There are some electrical tests.24-1
24-37

Throttle body control module, checking

Note: 

If the Throttle Body Control Module is replaced, the new assembly MUST BE matched to the Engine Control Module Page 24-134 .

Special tools, testers, measuring instruments and auxiliary items required 

VAG 1551/1552 Scan Tool with VAG 1551/3B adaptor cable 

VAG 1598/22 Test Box 

Fluke 83 Multimeter 

VW 1594 Adaptor kit 

Wiring diagram 

Note: 

Components of throttle valve control module -J338-: Throttle drive (power accelerator actuation) -G186-, Angle sensor -1- for throttle drive (power accelerator actuation) -G187-, Throttle Position (TP) sensor -G69- and Closed Throttle Position (CTP) switch -F60- 

All settings are made using VAG 1551 Scan Tool in Function 04 

If the complete Throttle Body Control Module has no current (e.g. connector disconnected) the throttle valve moves to a pre-determined mechanically determined position which will increase idle speed to 1200 - 1300 rpm when engine is at normal operating temperature. 

--------------------------------------------------------------------------------
24-38

If no current reaches the Throttle drive (power accelerator actuation) -G186-, the throttle will move to the mechanically predetermined position (emergency running gap), but because the Closed Throttle Position (CTP) switch -F60- is still recognized an almost normal idling speed of approx. 900 rpm is achieved by relatively retarding the ignition . 

If the Engine Control Module recognizes a DTC for the Angle sensor -1- for throttle drive (power accelerator actuation) -G187- the Throttle drive (power accelerator actuation) -G186- is switched to receive no current by the Engine Control Module and the throttle moves again to the mechanically predetermined position (emergency running gap). 

Closed Throttle Position (CTP) Switch -F60- 

- Connect VAG 1551/1552 Scan Tool Page 01-8 

- Switch ON ignition 

- Press 0 and 1 buttons to select "Address word" 01 "Engine electronics" 

Rapid data transfer HELP 

Select function XX 

Display will appear as shown 
- Press 0 and 8 buttons to select Function 08: "Read measuring value block" 
- Press Q button to enter input 

Read measuring value block HELP 

Input Display group number XXX 

Display will appear as shown 
- Press 0, 0 and 5 buttons to select "Display number 5" 
- Press Q button to enter input 

Read measuring value block 5 

1 2 3 4 

Display will appear as shown (1 to 4 Display zones) 
- Check the Closed Throttle Position switch (Display zone 4) 

--------------------------------------------------------------------------------
24-39


Display zones 

1 
2 
3 
4 

Display group 5: General engine data 

Display 
xxx rpm 
xx.xx ms 
xxx km/h 
Idle speed 
Part throttle 
Wide Open Throttle 
Overrun 
Enrichment 

Indicated 
Engine speed 
(in steps of 40) 
Engine load 
Vehicle speed 
Operating modes 

Working range 
0 to 6800 rpm 
0.00 to 8.50 ms 
--- 
--- 

Specification 
0 rpm 
0.00 ms 
0 km/h 
Closed throttle = 
engine idling 
Throttle valve slightly open = part load 


--- 
--- 
--- 
If specifications are not obtained Page 24-40 Continuation 


- Press button. 

- Press 0 and 6 buttons to select Function 06: "End data output" 

- Press Q button to enter input 

--------------------------------------------------------------------------------
24-40

Continuation of check when Display shows partly open throttle 

- Disconnect 8 pin harness connector from Throttle Body Control Module. 
- Bridge connector terminals 3 + 7 using jumper wires from VW 1594 and observe display. 
If display shows idling: 
- Press button. 
- Press 0 and 6 buttons to select Function 06: "End data output" 
- Press Q button to enter input 
- Switch OFF ignition. 
- Replace Throttle valve control module -J338-. 
If display shows Partially Open Throttle: 
- Press button. 
- Press 0 and 6 buttons to select Function 06: "End data output" 
- Press Q button to enter input 
- Switch OFF ignition. 
- Check Voltage supply of Throttle Body Control Module and wiring to Control Module Page 24-51 . 

--------------------------------------------------------------------------------
24-41

If Voltage supply and wiring OK 

- Replace Engine Control Module Page 24-128 . 

Continuation when display constantly shows idling 

- Disconnect 8-pin harness connector from Throttle Body Control Module. 
If Display shows Partially Open Throttle: 
- Press button. 
- Press 0 and 6 buttons to select Function 06: "End data output" 
- Press Q button to enter input 
- Switch OFF ignition. 
- Replace Throttle Valve Control Module -J338-. 
If Display shows idling: 
- Press button. 
- Press 0 and 6 buttons to select Function 06: "End data output" 
- Press Q button to enter input 
- Switch OFF ignition. 
- Check Throttle Valve Control Module Voltage supply and wiring to the Control Module Page 24-51 . 
If Voltage supply and wiring OK: 
- Replace Engine Control Module Page 24-128 . 

--------------------------------------------------------------------------------
24-42

Throttle drive (power accelerator actuation) -G186- and Angle sensor -1- for throttle drive (power accelerator actuation) -G187-, checking 

Test conditions 

Engine Coolant Temperature at least 85 C. 

Test sequence 

- Connect VAG 1551/1552 Scan Tool Page 01-8 

- Start engine and let idle 

- Press 0 and 1 buttons to select "Address word" 01 "Engine electronics" 

Rapid data transfer HELP 

Select function XX 

Display will appear as shown 
- Press 0 and 8 buttons to select Function 08: "Read measuring value block" 
- Press Q button to enter input 

Read measuring value block HELP 

Input Display group number XXX 

Display will appear as shown 
- Press 0, 5 and 5 buttons to select "Display group 55" 
- Press Q button to enter input 

Read measuring value block 55 

1 2 3 4 

Display will appear as shown (1 to 4 Display zones) 
- Check idle speed control specifications (Display zones 1 to 4) 

--------------------------------------------------------------------------------
24-43


Display zones 

1 
2 
3 
4 

Display group 55: Idle Speed Control 

Display 
xxx rpm 
x.xx g/s 
x.xx g/s 
xxxx 

Indicated 
Engine speed 
(in steps of 10) 
Idling air mass control value (idling regulator) 
Idling speed air mass learned value 
Operating mode 

Working range 
0 to 2550 rpm 
-2.8 to 4.17 g/s 
-1.94 to 2.22 g/s 
--- 

Specific. 
820 to 900 rpm 
-1.11 to 1.11 g/s 
-1.1 to 1.11 g/s 
0000 


If specifications are not obtained Page 24-44 , continuation 
If specifications are not obtained Page 24-45 , Evaluating Display group 55 
Significance 
Page 24-45 


If specification not obtained 

- Press button. 

- Press 0 and 6 buttons to select Function 06: "End data output" 

- Press Q button to enter input 

- Switch OFF ignition. 

--------------------------------------------------------------------------------
24-44

Continuation 

- Disconnect 8-pin harness connector to Throttle Body Control Module. 
- Switch Fluke 83 Multimeter to resistance range 
- Measure throttle valve positioner resistance between connector terminals 1 + 2. 
Specification: 3 to 200 
- Check Throttle Valve Control Module Voltage supply and wiring to Control Module Page 24-51 . 
If NO malfunction detected: 
- Replace Throttle Valve Control Module -J338-. 

--------------------------------------------------------------------------------
24-45

Evaluating Display group 55 

Display group: 55 



Display zone: 2 + 3 
Possible cause of malfunction 
Corrective action 

Greater than 1.11 g/s 
Load increased (consumers switched ON) 
Throttle valve mechanical components sticking 
Throttle valve air guide dirty in area of throttle valve mechanism 
- Switch OFF consumers 
- Visually check, correct cause as necessary 

Less than -1.11 g/s 
Unmeasured air behind throttle valve 
- Check Intake Air system for leaks (unmeasured air) Page 24-85 
- Check exhaust system 
Repair Manual, 1.8 Liter 4-Cyl. 5V Turbo Engine Mechanical, Engine Code(s): AEB, ATW, Repair Group 26 

Significance of 4 position Display 

Significance when Display position = 0 

x 
x 
x 
x 
(Display group 55) 




0 
A/C compressor OFF (0 = A/C compressor OFF / 1 = A/C compressor ON) 



0 

Transmission Range Selector lever in P or N position (0 = lever in P or N / 1 = lever in 2 / 3 / 4 / R / D) 


0 


Always "0" 

0 



Always "0" 


--------------------------------------------------------------------------------
24-46

Throttle Position (TP) sensor -G69-, checking 

Test conditions 

Coolant temperature at least 85 C. 

Test sequence 

- Connect VAG 1551/1552 Scan Tool Page 01-8 

- Switch ON ignition 

- Press 0 and 1 buttons to select "Address word" 01 "Engine electronics" 

Rapid data transfer HELP 

Select function XX 

Display will appear as shown 
- Press 0 and 8 buttons to select Function 08: "Read measuring value block" 
- Press Q button to enter input 

Read measuring value block HELP 

Input Display group number XXX 

Display will appear as shown 
- Press 0, 0 and 3 buttons to select "Display group 3" 
- Press Q button to enter input 

Read measuring value block 3 

1 2 3 4 

Display will appear as shown (1 to 4 Display zones) 
- Read off throttle valve angle in Display zone 3. 

--------------------------------------------------------------------------------
24-47


Display zones 

1 
2 
3 
4 

Display group 3: Load registration 1 

Display 
xxx rpm 
xx.x g/s 
xxx 
xx.x BTDC 

Indicated 
Engine speed 
(in steps of 40) 
Air mass 
Throttle valve angle 
Ignition timing angle 

Working range 
0 to 6800 rpm 
--- 
0 to 90 
0.0 to 50.0 BTDC 

Specification 
0 rpm 
--- 
0 to 5 
0.0 ATDC 


- Slowly but fully open throttle, observe angle in Display zone 3 

Value must increase uniformly over the complete range. 

- Press the button. 

- Press 0 and 6 buttons to select Function 06: "End data output" 

- Press Q button to enter input 

- Switch OFF ignition. 

Note: 

The displayed value is dependent on the tolerances of the Throttle Position sensor and does not correspond to the actual opening angle.

--------------------------------------------------------------------------------
24-48

If the value does not increase uniformly: 

- Replace Throttle Valve Control Module -J338-. 

If the display constantly shows 0 or is above 90 : 

Display 
Cause 
Continue of check 

0 
Open circuit or short to positive 
Page 24-48 

above 90 
Short to Ground 
Page 24-49 


Continuation of check when display 0 : 

- Disconnect 8-pin harness connector to Throttle Valve Control Module. 
- Bridge harness connector terminals 5 + 7 using jumper wires from VW 1594 adaptor kit and observe display. 
If display is above 90 : 
- Press button. 
- Press 0 and 6 buttons to select Function 06: "End data output" 
- Press Q button to enter input 

--------------------------------------------------------------------------------
24-49

- Switch OFF ignition. 

- Replace Throttle Valve Control Module -J338-. 

If Display is 0 : 

- Press button. 

- Press 0 and 6 buttons to select Function 06: "End data output" 

- Press Q button to enter input 

- Switch OFF ignition. 

- Check Throttle Valve Control Module Voltage supply and wiring to Control Module Page 24-51 . 

If Voltage supply and wiring OK 

- Replace Engine Control Module Page 24-128 . 

Continuation of check when Display is above 90 : 

- Disconnect 8-pin harness connector to Throttle Valve Control Module. 
If Display is 0 : 
- Press button. 
- Press 0 and 6 buttons to select Function 06: "End data output" 
- Press Q button to enter input 

--------------------------------------------------------------------------------
24-50

- Switch OFF ignition. 

- Replace Throttle Valve Control Module -J338-. 

If display is above 90 : 

- Press button. 

- Press 0 and 6 buttons to select Function 06: "End data output" 

- Press Q button to enter input 

- Switch OFF ignition. 

- Check Throttle Body Control Module Voltage supply and wiring to Control Module Page 24-51 . 

If Voltage supply and wiring OK: 

- Replace Engine Control Module Page 24-128 . 

--------------------------------------------------------------------------------
24-51

Voltage supply and wiring to Control Module, checking 

- Disconnect 8-pin harness connector to Throttle Valve Control Module. 
- Switch Multimeter to Voltage range 
- Connect Multimeter between connector terminals 4 + 7. 
- Switch ON ignition. 
Specification: 4.5 Volts minimum 
- Switch OFF ignition. 
- Connect Multimeter between connector terminals 3 + 7. 
- Switch ON ignition. 
Specification: 9 Volts minimum 
- Switch OFF ignition. 

- Connect VAG 1598/22 Test Box to Engine Control Module harness connector. 

--------------------------------------------------------------------------------
24-52

- Check wiring for open circuit between Test Box and harness connector using Wiring diagram. 
Terminal 1 + socket 66 
Terminal 2 + socket 59 
Terminal 3 + socket 69 
Terminal 4 + socket 62 
Terminal 5 + socket 75 
Terminal 7 + socket 67 
Terminal 8 + socket 74 
Wire resistance: Max. 1.5 
- Check wires for shorting to one another. 
Specification: 
If wiring OK 
- Check Engine Control Module Voltage supply Page 24-121 . 

--------------------------------------------------------------------------------


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## chris86vw (Feb 23, 2000)

*Re: 99 passat won't IDLE. Please help. "OBD Code P1545" (danandjonna)*

Ok, way to long of a post for a simple thing but thorough..
Cable cars still have motors in their TBs to maintain the idle. It is very common that when the ECU loses power whether its out to be chipped or the battery goes dead that they dont' idle once power is restored.. All you need to do is remove the TB, clean the area around where the plate seals.. then do a throttle body alignment all will be well. I have never seen a cable passat need a TB replacemet for this or any other issue, so its very unlikely that you will need a new one.


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## Tony68 (Jan 13, 2011)

What do you mean by TB Alignment? Is that done by computer or do you mean physically aligning it after cleaning it?

I'm having the same problem right now including the battery as well. It's a 99 Volkswagen Passat 1.8 Turbo Automatic AEB engine.

I did a rebuild and the car wouldn't start, it kept flooding. I did get it to start and even idle but it would stall. Also it seemed like it was running really rich and there was a lot of black smoke coming out of the exhaust. Then the computer said that it was the Throttle Position Sensor so I changed it and the car started but then it would stall as before. When I would try to accelerate while driving the car it would start to stall as if I wasn't getting enough fuel delivery. The computer (Maxi-Scan) said that the 1st injector was bad so I changed it but still had problems. Then the computer said it was the Throttle Position Malfunction P-1545. The couple of times I actually tried to drive it the car would kick into gear very abrasively even after filling it with transmission fluid. Can you help me with this.

Thanks,


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## VdubzJetta (Dec 16, 2010)

clean your throttle body and then find someone with a vagcom or take it to the dealer and the would need to do it with the computer it should be fine after that


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## MAD*TOYZ (Mar 24, 2012)

*''p1545 problem fix''*

I had the same code p1545 tps. I did see a post about someone saying it could be the ecu. My car does turn on but you give it gas an it turn of. I bought the car like that an dint come with a battery. The previous owner replace a use tpc dint fix the problem. So i call my locall vw dealership set appointment. So that p1545 code was fix my ecu needed to be updated an the tps to. They said it could of happen because the battery was pull off or car sat for a long time an drain the battery. Yes that car did sat for a long time 2 years an no battery.............hope will help out to some of you


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## Incorporate (Nov 6, 2016)

Anyone within this thread that was receiving the Fault code do the TB Alignment? and did it fix the issues. I have a Similar issue on my 99 Passat 2.8l It will Idle but when I give it gas and hit the 1200 RPM it drops to 1000 RPM and Throws the Fault Code. I did replace the TB but trying to find someone with a VAGCOM to do the Realign so I don't have to pay the Dealers 150 bucks for a Simple job.


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## zexiong78 (Nov 27, 2017)

*About Code P1545*

My 1999 Passat 1.8t had a code P1545 too and today I changed the throttle body and cleared the codes and it has not returned yet. Before the replacement, the code would return in a few minutes so I would have to say that the code P1545 is due to a bad throttle body which is the bad news because at brand new it is expensive around over $400.  But here is the good news, today I was able to get a used one from the junkyard at 50% off for only $23! So my point is if you get a p1545 code you can replace your throttle body with a used one from the junk at much lower cost than new or at the dealer.


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