The check valve between the intake and the booster .not sure in which direction the non return air in the valve should flow

Question edited for clarity.
Question moved to model category.

This is a strange code that doesn't appear to have one definitive reason, it's a bit of "you have a bit of a problem, but we aren't sure". Just Answer dot com mechanic says it is the MAF Sensor.

https://p1004-volvo.autotroublecode.com/

http://p1004.engine-trouble-code.com/

I have a 99 s70 volvo that has a p1004 code. I've been told

JustAnswer https://www.justanswer.com > volvo > iq32q-99-s70-v...
Feb 12, 2022 - On newer vehicles, the P1004 is for the short runner valve which is internal to the intake manifold and makes sure there is even air ...

1 answer · Top answer: HI This is 100% unrelated to your original question. I will answer this as a courtesy, but ...

Have 1999 Volvo S70 Non-Turbo. Codes are P0420, ...

AutoCodes https://www.autocodes.com > have-1999-volvo-s70-n...
Apr 24, 2017 - Have 1999 Volvo S70 Non-Turbo. Codes are P0420, P0645, P1004, P1081, Symptom= intermittent stall. NO Check engine light on. Seems to accelerate ...

the fuel filter is it a inline type filter if so check the arrow on the filter make sure the fuel is flowing in the right direction because some of these filters have a non return valve in them.a garage made this mistake with my brothers car, hope this helps its worth checking. it sounds like a restriction of fuel

Mass Air Flow sensor just measures incoming air flow at a predetermined rpm/load. The computer is saying the flow measurement is not correct. This can be caused by mechanical faults within the engine like a bad valve seat or timing chain but would generally be accompanied by backfires through the intake. Usually its caused by a vacume leak between the sensor and the intake valve,like the intake manifold,loose intake pipe clamps, broken vacume lines,a leaking vacume brake booster [it will hiss loud when you apply the brake],bad spark plugs/wires, a clogged catalytic converter, stuck open egr valve or pcv valve,bad oxygen sensor or even a very clogged air filter. I know there is a lot listed but the MAF or MAP sensors show general flow through the engine that can be affected by several things. A vacume tester from your local auto parts store is about 30bucks and usually has instructions how to test for vac. leaks within the engine also to determine a if thers is bad valve seat or clogged exhaust.

if you remove the turbo from that car, the car will not run very well because the computer is setup to run with a turbo device, it need the air flow to force the fuel where it need to go. after removing the turbo you are going to have fuel issue, stay running, be fore you buy it go to the owner ask if they would mind if you or them disconnect the belt from the turbo charger and restart the car, see how well it runs, try and drive it, if every thing works okay, than buy the car and leave the belt off the charger.

Sounds like you could have an aux air regulator valve, that is not working when it will not work; there is no fast idle cold. Should be around 1500 rpm cold, the car will stall out and pop through the intake when bad. You have a digital volt meter to do some testing with to make sure the mass air flow is working correctly.

Also, check the plugs for how they're burning, check the air filter for good flow, do a compression test and judge from there. Intake backfire is usually caused by running lean or improper timing.

For the 79 model zx, ignition timing was 10 degrees BTDC @ 700rpm
For 80 and up zx, non turbo - 8 degrees BTDC +- 2 degrees @ 700rpm
turbo - 20 degrees BTDC +- 3 degrees @ 700 rpm

Also done with distributor vacuum advance hose removed and plugged.
NOTE:
* BTDC = Before Top Dead Center
* + - = Plus or minus
Hope thos helps; keep us updated.

May have a faulty air/fuel ratio sensor or o2 sensor, throttle body may need adjusting or have a stretched spring or there may be grime restricting air flow so it's flooding it.

Can you borrow an ignition coil and/or control unit for a day or two to check for the misfires?
The "Secondary Air System" should not be the problem since it merely is some air that gets blown into the exhaust line to increase start-up speed of catalytic cleaning. P0410 indicates a malfunction of this additional air system. This might be caused by the non-return valve in the air flow, the lambda sensor, or the air pump (which the turbo does not have, as far as I know). The valve is not too easy to get to but is quite often the source of the problem.

Good luck
Ingo

It is probably either the N75 valve(Diverter Valve) or the wastegate actuator. Usually a significant boost leak will set a DTC, still check all hoses and clamps.

A bad wastegate actuator or flap would cause no boost but not necessarily the air-sound.

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Testing N75

Air Bypass Valve: Testing and Inspection
With Generic Scan Tool
Wastegate Bypass Regulator Valve, Checking
Recommended special tools and equipment e.g.:
- VAG1526 multimeter or VAG1715 multimeter
- VAG1594 connector test kit
Test sequence
- Switch ignition off.
- Disconnect connector at solenoid valve for boost pressure regulation.
- Measure resistance between terminals of valve.
Specified value: 25...35 Ohm
If specified value is not obtained:
- Replace Wastegate Bypass Regulator Valve -N75-.

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Testing N249

Exhaust Bypass Valve: Testing and Inspection
With Generic Scan Tool
Recirculating Valve For Turbocharger, Checking
NOTE: Valve opens between connection to intake manifold and connection to deceleration shut-off valve with no voltage. Connection to vacuum
reservoir is closed.
Test sequence
- Switch ignition off.
- Disconnect connector from Recirculating valve for turbocharger -N249-.

- Measure resistance between terminals of valve.
Specified value: 27...30 Ohm
If specified value is not obtained:
- Replace Recirculating valve for turbocharger -N249-.
If specified values are obtained:
- Connect test box to control module wiring harness, connect test box for wiring test.

- Check wire between test box socket 105+2-pin connector terminal 2 for open circuit according to wiring diagram.
Wire resistance: max: 1.5 Ohm
- Also check the wire for short circuit to B+ and Ground (GND).
If no malfunctions are found in wire:
- Check wire between 2-pin connector terminal 1 and the Fuel Pump (FP) Relay -J17- for open circuit according to wiring diagram.
Wire resistance: max: 1.5 Ohm
If no malfunctions are found in wires:
- Replace Engine Control Module (ECM).

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To test the wastegate, locate the wastegate linkage rod and verify that there is no play and that it is closed. You can apply compressed air to the actuator to see if it opens and closes. (not more than 30 psi)

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Vehicle: Vacuum and Vapor Hose Diagrams
System Diagram
Vacuum Diagram
1 From fuel tank
2 EVAP canister
- with Evaporative Emission (EVAP) Canister Purge Regulator Valve -N80-
3 Check-valve for EVAP canister
- Between EVAP canister and intake manifold before turbocharger Installation position (light/dark side): Arrow points in direction of flow, as
shown
4 Turbocharger
5 Pressure unit for boost pressure regulation
6 Mechanical recirculation valve
7 Brake booster
8 Check-valve
- Between brake booster and intake manifold
- Installation position (light/dark side): Arrow points in direction of flow, as shown
9 Wastegate bypass regulator valve -N75-
10 Mass Air Flow (MAF) sensor -G70-
11 Air cleaner housing
12 Pressure control valve for crankshaft housing ventilation
13 Vacuum reservoir
- Bolted on at cylinder head
14 Charge air cooler
- With charge air pressure sensor -G31-
15 Fuel pressure regulator
16 Throttle valve control module -J338-
17 Intake manifold
- With Intake Air Temperature (IAT) sensor -G42-
18 Crankcase ventilation
19 Check-valve
- Installation position (light/dark side): Arrow points in direction of flow, as shown
20 Recirculating valve for turbocharger -N249-
- Component location Fig. 1
21 Check-valve
- Between EVAP canister and intake manifold
- Installation position (light/dark side): Arrow points in direction of flow, as shown
22 Charge air cooler

It sounds as if your brake booster check valve or brake booster itself has failed, allowing vacuum to both sides of the chamber.

You can verify this by pulling the vacuum hose off the brake booster and plugging the hose, then starting the car and seeing if brake pedal operation is normal. **do not drive like this you will have no brake power assist**

If it operates normally, check the check valve that air flow only goes in one direction through it. If normal, replace your brake booster.

we have the same car, i would have a mechanic check the ECU. thats the first step in finding out what is wrong and why its burning so mutch fuel. it could also be your air filter, but then agian, you wouldnt be burning a tank of gas a day. well hope you get it fixed.