Pretty sure it has to be in POS II.

I ran mine last week, it had a lot less fuel in it. Doesn't it say the requirements on the screen before that?

Maybe you're borderline on the fuel. Burn some off.

 

If the test stops or does not start as indicated, replace the LDP and retest.
LDP is not monitored for function.
EVAP code was set because the ECM did not detect a completed, passed evap cycle.
The click is the closed check valve in the LDP activating not the pump running.

 

I have 39L according to VIDA (which is 63% full). The requirements say 15-85%.
I tried running it in POS II both running and not running. When it was not running the engine was cold.
Did you run the test with the car running , not running (cold) or not running (hot)? Wish it would post an error message.

 

To replace the LDP is going to be a lot of fun. It is really wedged in there. I am worried about dropping the frame.

 

I tested with the engine off. Battery held for the 10 or so minutes it needed. Engine was cold and really shouldn't matter.

This is how I changed mine - it wasn't that bad - no sub frame drop - fwd:

https://www.swedespeed.com/threads/...the-leak-detection-pump-ldp.690267/?post_id=8388410&nested_view=1&sortby=oldest

 

Did you physically bend a bracket?

 

Figure I will also warn people about a mishap I had. I tried to smoke test the vehicle while running. I activated the LDP (closed the backend) and started to smoke the system. Then after a little while I heard a POP! I looked under the car and realized my mistake (tank was somewhat indented or caved). I had not disconnected the purge valve on the intake. The ECM commanded it open and the fuel tank was now under engine vacuum. Realizing this I opened the LDP. Heard another pop, I think it survived but that was a close call.

 

Odd, gas cap should have prevented excessive pressure/vacuum.

 

If I read correctly ECM-4308 is a large leak like P0455. When I had P0455 it was the evap purge valve that failed (random sticking open or closed depending on the minute). At least check the purge valve hose going to the intake manifold and make sure the valve isn't stuck open. Also be sure the gas cap seal is in good shape.

 

The purge valve was the first thing I checked because when I idle my fuel trim (LTFT) is negative by 4-7%. When I drive it goes back to very normal levels. I thought this might be the purge valve sticking open and allowing fuel vapor and the ECM was leaning out to correct this. When I blow into the valve it feels closed and when I apply power it flows freely.

 

If the MAF reading is high then the fuel trim issue could be the vacuum ejector is partially clogged.

My purge valve would stick during bench testing,

 

Hi SpaceRay, not sure I completely follow. What are you referring to when you say vacuum ejector? Would you explain what I should be checking?

 

See this thread and check symptoms for a match: https://www.swedespeed.com/threads/ecm-250a-long-term-fuel-trim-lower-limit-p0172-–-system-too-rich-bank-1.401201/

Not necessarily the code symptoms.

Edit: The easy check is to remove the hose to the air box and see if there is good suction.

 

I know that thread. The venturi line is what you are referring to. I checked mine, it is fine.

 

Thanks for the help. I will work on replacing with a new LDP.

I'm guessing the fuel trim anomaly is probably related to something else or that purge valve is faulty but tests ok on the bench for some reason.

 

Thanks for the help. I will work on replacing with a new LDP.

I'm guessing the fuel trim anomaly is probably related to something else or that purge valve is faulty but tests ok on the bench for some reason.

I wish you luck with it. Even after changing the LDP I still get random P0442 and P0441. I ran the Vida evap test last week and it passed and got P0441 a few days later - may or may not be related. Still waiting to see if the P0442 reappears after putting on a new gas cap that actually stays tight.

 

I used a Bosch branded pump.

As far as the cheap pumps. It depends on how many times you're willing to do the job - and cost consideration too.


I'm not sure about the LDP being the issue either. I would cut the vent line and manually pressure test to max 1 psi - like was done here (see post #20): https://www.swedespeed.com/threads/...evap-from-hell-code-p0442-and-now-add-p0441.684697/?nested_view=1&sortby=oldest
This would test the entire system except the pump's ability to seal. Only if the pressure holds would I replace the pump. If the pressure doesn't hold you will have to find the leak - still could be the pump - case cracked or internal valve doesn't seal when closed.

If the pump was completely dead Vida should have thrown a code for it. I'm a Vida noob so I have no idea why it refuses to do the test for you.

 

Thanks and I hope your issues clears up as well. BTW, which LDP did you go with? I see expensive OEM, a Bosch and a ton of no-names that list for all kinds of models like JLR, etc.

Also, still amazed that if the pump feature of the LDP is not working it will set a code for a leak (ECM-4308). How does the ECM know there is a leak if it cannot run the test? Maybe I am not interpreting it correctly though. Any clarification would be appreciated.

@volvogod already answered

If the test stops or does not start as indicated, replace the LDP and retest.
LDP is not monitored for function.
EVAP code was set because the ECM did not detect a completed, passed evap cycle.
The click is the closed check valve in the LDP activating not the pump running.

4308 from what I remember at the dealer was the death code for LDP.
I'd suggest at minimum getting the correct Bosch unit. From what I remember, the S40 is not fun to do twice.

 

The LDP is definitely wedged in there. Looks like I may be able to get a Torx on those 3 bolts holding it. I guess the issue is that after unbolting it there won't be enough room to maneuver it out?

 

If you bend the bracket there will be enough space to get it out. If you're reluctant to bend a bracket on a 20 year old car then you'll have to find another way to get it out.

As was said by volvogod, the factory Volvo clamp may be a PITA. A Dremel might be able to get at it. Mine already had a worm clamp on it so I didn't have to deal with it.

Side note: If you ever had the desire/need to put in adjustable rear camber arms, now is the time to do it.

 

V50 LDP replace PDF, same location as S40.
Replace with hose clamps. Volvo crimp clamp is hard to access.
You can get in there without dropping the shock/axle assembly.
We also had a lift that helped a lot.

 

Thanks volvogod, I will get the part and start unbolting.

 

I did the job using the bracket bending technique. It was extremely frustrating to get the LDP out. Mine was the original and the Oertiker type clamp meant I had to get the vent pipe out the back first. Interestingly, the original Bosch unit comes apart very easily. I might play around with it and see what went wrong.

 

What is the function of the white wires going into the pump?

 

A dremel should have been able to get at that clamp. I was lucky on mine since the LDP had been changed before and had a worm clamp on it.

This LDP has the pump itself, vent valve and what is either a pressure sensor or a heater.
I'm guessing that's the pressure sensor. Something has to measure it. I'm not aware of another sensor for this - I could be wrong...

There are specific resistance readings on certain pins. Don't recall what those readings are though. I'm sure they can be found again via internet searching.

Looking at the car's wiring diagram pins on the pump:
1: Motor control (black/white stripe)
2: Sensor/heater? (White/violet stripe)
3: Solenoid Yellow/violet stripe)
4: Motor positive (Green/blue stripe) - other side of sensor/heater? is also connected here.

 

The solenoid and the pump 12V motor work when I energize them. I wonder what failed? I found this in the wiring diagram. I think the reason this LDP has 4 pins is due to a PWM (controlled by LIN) between pins 2 and 4. Do you know what the round thing with the triangle and circle is? Only thing I can think of is that is the symbol for a pump. That symbol is not defined, at least I cannot find it.

Does it sense pressure (like a MAP) or is the ECU measuring the current draw during different parts of the test and comparing it to reference currents when it does a "calibration" pump through an defined orifice?

 

It doesn't make sense that symbol is Lin going to pin 4 which is the 12v power line. That has to be a sensor or heater. They could easily control the motor using pin 1. That motor in your photo looks like a junk motor used in old RC cars.

That funky symbol translates to an egyptian meaning of you're f****d (joke of course). I agree that symbol is the pump.

The evap test measures in pa - when I ran the test it went to something around 3500pa. It would make more sense to measure the actual pressure than the current but hey maybe that's why the system is unreliable. Measuring current flow through a ~6 foot wire through multiple connections sound like an engineering nightmare - stupid design if this is how it works.

About that calibration hole. If my problem continues I was thinking of enlarging the hole to trick it.

 

Funny you mention enlarging the hole. When I was reading about how this thing works I had the exact same thought, just change the denominator.

When you ran the EVAP test in VIDA, did you do it with the car on?

 

Car was in POS II. Engine off.

 

ECM monitors LDP current draw for EVAP test.
ECM converts amp draw to Pa for EVAP test screen.
Below is VIDA Design, Function for EVAP.
EVAP test will run during the night sometime when car is cooled down and turned off.
ECM decides when the EVAP needs to be tested.

The function of the leak diagnostic unit is to pressurize the fuel tank system during leak diagnostics.
The leak diagnostic unit consists of a plastic housing with:
electrical air pump
a valve / solenoid which governs the air flow in the unit
a heater element (PTC resistor) which warms up the pump.
The electrical pump, valve and heater element in the unit are supplied with voltage by the system relay. The pump, valve and heater element are grounded (control) in the engine control module (ECM).
When leak diagnostics are not active, the valve is held open to ambient air for EVAP control to be carried out.
During leak diagnostics the pump in the leak diagnostic unit starts. The valve in the unit is operated by the engine control module (ECM) by grounding the different circuits internally in the engine control module (ECM).
The Engine control module (ECM) checks the fuel tanks system for leaks by pressurizing the system and at the same time monitoring a number of relevant parameters. Also see: Leak diagnostics (certain markets only)
The engine control module (ECM) can diagnose the leak diagnostic unit.
The valve in the leak diagnostic unit can be activated.
The leak diagnostic unit is at the upper front edge of the fuel tank.
Leak diagnostics (certain markets only)

To minimise false detection of leakage, new software has been released for the Engine control module (ECM). The software has been released afterwards, in order of priority, started at the end of 2006.
To check the current software version, see Vehicle communication in VIDA.
The improved software version makes diagnostics more robust and durable against aging and wear of the leak diagnostic unit. It affects strategies, behaviour and to a degree also read off parameters.

All gases that evaporate from fuel in the fuel tank must be led to and stored in the evaporative emission system (EVAP) canister so that they can be directed into the engine for combustion. In order to detect leakages which cause evaporation of gases into the air, the fuel tank system is diagnosed for leakage. The fuel tank system consists of:
fuel tank
the EVAP canister purge valve (1)
EVAP canister (2)
leak diagnostic unit (3)
air cleaner (ACL) (4)
Roll-over valve (5)
Float Limit Vent Valve (6)
fuel filler pipe (7)
all lines between the above components.

The fuel tank system has a leak diagnostic unit to diagnose any leakage. The leak diagnostic unit pressurizes the fuel tank system when the conditions for leak diagnostics are met.
The control module can detect faults in the function of the leak diagnostic unit and leakage that is 0.5 mm or greater. Minor leak; leakage greater than 0.5 mm but less than 1.0 mm. Major leak; leakage greater than 1.0 mm.

The leak diagnostic unit consists of a pump and a valve that controls the air flow in the unit. The Engine control module (ECM) checks for leakage in the fuel tank system by measuring the relationship between reached pressure and flow from the leak diagnostic pump during pressurization.
If a certain pressure is not reached with a predetermined supplied flow (with known mass), the Engine control module (ECM) interprets this as a leak from the fuel tank system.

Leak diagnostics starts in normal operation when specific conditions are met, see below. The diagnostics can also be started on command using VIDA when some of these conditions are ignored.

Conditions for diagnosis
The diagnosis begins when all the following conditions are met.
Note: When diagnostics are started on command using VIDA, certain different conditions apply. See relevant information about these, available with starting Quick test fuel tank system.

No diagnostic trouble codes (DTCs) for EVAP valve or atmospheric pressure sensor may be stored.
The engine is switched off until the engine coolant temperature (ECT) has fallen to a few degrees above the outside temperature, then engine running for at least 10 minutes
Ignition off
Vehicle speed 0 km/h.
Engine coolant temperature (ECT) 4-35°C.
Maximum altitude of 2500 meters above sea level
Outside temperature 4-35 °C.
Fuel volume in the tank between 0-85 %. The engine control module (ECM) ignores these parameters if a diagnostic trouble code (DTC) is stored for the fuel level sensor and the fuel volume cannot be determined.
Battery voltage between 11-15 V. The voltage must be stable.
EVAP canister purge valve closed
Low volume in the canister.
Fuel tank filler cap locked. Tip. Locking occurs when the vehicle speed exceeds approximately 20 km/h.

Diagnostic phases
The diagnostic is divided into the following phases and is carried out in sequence when all conditions for the diagnostic have been met.

reference phase
function test
checking the fuel tank system

Reference phase
Before the leak diagnostic begins, the control module runs a reference phase for leakage. During the reference phases for leakage that is 0.5 mm, the pump in the leak diagnostic unit pumps ambient air through a 0.5 mm hole and back out to the ambient air. At the same time, the pump in the leak diagnostic unit is monitored and the reference values stored for later use to determine whether the tank system is leaking or not.
If a reference value for the pump is outside its unexpectedly high or low, or deviates too much, diagnostics is cancelled and a DTC is stored.


Function test
After the reference phase, the valve in the leak diagnostic unit is activated and controls the air flow to the fuel tank to pressurize the fuel tank system. This change of air flow will cause the load the pump to fall briefly before the pressure builds up in the fuel tank system. If the load does not change within permitted parameters within a permitted time, diagnostics is cancelled and a DTC is stored.


Checking the tank system, major leak (leak greater than 1.0 mm)
Diagnostics are carried out every time conditions for diagnostics are met.
The leak diagnostic unit pressurizes the fuel tank system and checks for leaks by monitoring the pressure the fuel tank system. The pressure is a calculated pressure, calculated using the measured pump power consumption. If the pressure stabilises and/or does not exceed 1500 Pa within 450 seconds, this is interpreted as a leak from the fuel tank system. Diagnostics are cancelled and a DTC for major leak is stored.


Checking the fuel tank system, minor leak (leakage greater than 0.5 mm but less than 1.0 mm)
The diagnostic for minor leaks is run every other time that the conditions for the diagnostic are met. Otherwise diagnostics stop after checking for major leaks.
The leak diagnostic unit continues to pressurize the fuel tank system. The Engine control module (ECM) checks for leakage in the fuel tank system by measuring the relationship between reached pressure and flow from the leak diagnostic pump during pressurization. In a sealed system the relationship between these must be linear. Any deviations from the linear relationship are calculated and used to determine how well sealed the tank system is.
A diagnostic trouble code (DTC) is stored if a minor leak is detected within 15 minutes.

 

Awesome. Let's measure current through a wire and multiple connections which will change resistance with heat and age. Then add a power source that will also change voltage over time - I hope they at least use a regulated voltage.

Hmm. Maybe I can fudge one these parameters while the car is turned off to avoid the test altogether.. Coolant temp would be easy enough. LOL.

 

it's funny how they sometimes engineer these things in a backwards way;
my P2 was throwing a number of codes once including "brake disc temperature too high"
but of course there's no temperature sensor anywhere near the rotors.. it used the brake pedal position sensor to determine that the pedal was depressed for too long time. problem was the position sensor was dead, so really had no idea where the pedal was.