Quick Diagnosis for VW/Audi GDI fuel pumps

Chris from Commack Diagnostician Posted   Latest   Edited  
Tech Tip
Driveability
P310B
Low Fuel Rail Pressure

One of the most common issues with VW/Audi GDI, or all GDI would be your P310B LOW FUEL RAIL PRESSURE code. This code, for those not familiar with the system can throw you through a loop. There have been many high pressure fuel pumps replaced multiple times, only to have the same code return. 

What can we do??? 

For VW/Audi, measuring value blocks (MVB) 103 and 106 are going to be your best friends. MVB 103 is going to show you your fuel line (low side) fuel pressure. Don't take this number for granted as this is an inferred measurement on later vehicle. MVB 106 will show you the fuel rail (high pressure) pressure and electric fuel pump duty cycle. 

General rule of thumb with GDI electric fuel pump is 50% duty cycle at idle. Too much more than that, the pump can't keep up providing fuel to the high pressure side. Looking at the scan capture, you can see the low and high pressure look ok-ish. 50 bar (740 psi) high side, and 4.48 bar (65 psi) low side.

Take a close look at the duty cycle. This pump is screaming at 83% at idle. There is no way that that pump can keep up under load. This in tank pump needs to be looked at closely. Most likely the pump needs replacement, but I will never recommend replacement without some basic checks.

After replacement, this is what MVB 106 should look like. 

Thanks for reading

+7

Aaron from Gardiner

 

Owner/Technician
 

Great post Chris! Thanks

0

Joe from Jersey City

 

Diagnostician
 

Hey Chris thanks for the awesome write up. I have a question about your choice of scanner. It looks like this is a factory tool. To the best of your knowledge would this fuel pressure information be available in detail on an aftermarket scanner? Not necessarily the generic mode but enhanced mode. Or is it your choice to always pick an OE scanner for this analysis?

0

Chris from Commack

 

Diagnostician
 

This is the Ross-Tech VCDS. While being close, it is by no means a factory scan tool. Measuring value block can be reached with almost any scan tool. You just need to know what they are. You can get this same info with a Lauch, Snapon, Autel, OTC, Gscan etc....

+2

Joe from Jersey City

 

Diagnostician
 

Awesome thanks again Chris

0

Hans from Salt Lake City

 

Diagnostician
 

Personally, the way the information is laid out in VCDS is the way I'm used to it. I can find the same info in my Launch and Autel, but it comes in a large list you have to scroll through. The measuring block numbers are the same however.

You can also test drive it with the scanner watching the in tank fuel pump duty cycle and watch it peg towards 100% during acceleration, showing it is having a hard time keeping up with fuel delivery. Keep an eye on the O2 sensors at the same time and watch some cool stuff. Use your graphing function!

+4

Geoff from Lahaina

 

Diagnostician
 

I was gonna ask that same question, so thank you also. We never want to work on German cars here but they get towed-in sometimes anyway, due to our location (at the edge of civilization).

+2

Chris from Commack

 

Diagnostician
 

That's my reason for presenting the information this way. I purposely try to not use VW terms for parts and data. Once you get past some of these idiosyncrasies of these vehicles, you come to realize they are just normal cars. 4 strokes, put some gas in it, hook up a battery, and you're good to go. 

Ok, maybe not that simple.

The GDI rules of thumb generally apply to all vehicles, That's why I figured this would be a good tip.

+1

Geoff from Lahaina

 

Diagnostician
 

I've never even heard of "measuring blocks" until your post. It's a whole different world.

0

William from Ashland

 

Diagnostician
 

On the Snap-On line it is under expert mode. When you first hook to the vehicle and ID it, it asks if you want vehicle specific or expert mode. The hard part is knowing what blocks to look at, and what the numbers are telling you.

0

Chris from Commack

 

Diagnostician
 

Measuring Value Blocks (Gasoline Engines)

• 00 General Engine Data - Summary • 01 Engine Idling Test • 02 Engine Idle - MAF Sensor / Injection Timing • 03 Engine Idle - Timing / Throttle • 04 Engine Idle - Intake / Coolant Temperatures • 05 Engine Functions - Idle Control / Operating Mode • 06 Engine Functions - Fuel Trim • 07 General Engine Data - BDE • 08 General Engine Data • 09 Oil Fill Level / Fuel Consumption • 10 Ignition at Idle - Load / Timing • 11 Ignition at Idle - Temperature / Timing • 12 Distributor Adjustment • 13 Injection Quantity Deviation (TDI Only) • 14 Misfire Recognition - Total • 15 Misfire Recognition - Cylinder 1-3 • 16 Misfire Recognition - Cylinder 4-6 • 17 Misfire Recognition - Cylinder 7-9 • 18 Misfire Detection Limits • 19 Misfire Recognition - Cylinder 10-12 • 20 Timing Retard - Cylinder 1-4 • 021 Timing Retard - Cylinder 5-8 • 22 Timing Retard - Cylinder 1 & 2 • 23 Timing Retard - Cylinder 3 & 4

• 24 Timing Retard - Cylinder 5 & 6 • 25 Timing Retard - Cylinder 7 & 8 • 26 Knock Control - Cylinder 1-4 • 27 Knock Control - Cylinder 5-8 • 28 Knock Sensor Test • 30 Lambda Control - Sensor Status • 31 Lambda Control - Sensor Voltages • 32 Lambda Control - Mixture Adaptation • 33 Lambda Control - Summary • 34 Lambda Control - Aging Check - Bank 1 / Bank 3 (Pre-Cat) • 35 Lambda Control - Aging Check - Bank 2 / Bank 4 (Pre-Cat) • 36 Lambda Control - Sensor Readiness - After Catalyst • 37 Lambda Control - Delta Lambda - Bank 1 • 38 Lambda Control - Delta Lambda - Bank 2 • 39 Lambda Control - Sensor Exchange • 40 Lambda Sensor Heating Resistor - Combined Wires / Heaters • 41 Lambda Sensor Heating - Bank 1 • 42 Lambda Sensor Heating - Bank 2 • 43 Lambda Sensor Aging - Bank 1 (Post-Cat) • 44 Lambda Sensor Aging - Bank 2 (Post-Cat) • 45 NOx Memory Catalytic Conversion • 46 Catalytic Conversion Test Bank 1 • 47 Catalytic Conversion Test Bank 2 • 48 Thermal Cat. Conversion Diagnosis - Bank 1 • 49 Thermal Cat. Conversion Diagnosis - Bank 2

• 50 Engine Speed Increase • 51 Engine Speed Increase - Gear Shifts • 52 Engine Speed Increase - RPM Regulation • 53 Engine Speed Increase - Generator Load • 54 Closed Throttle Position Switch • 55 Idle Speed Stabilization • 56 Idle Speed Stabilization • 57 Idle Speed Stabilization - Air Condition • 58 Engine Mounting • 60 Electronic Throttle Body Adaptation • 61 E-Gas Adaptation • 62 Electronic Throttle • 63 Electronic Throttle - Kick-Down Adaptation • 64 Throttle Body Potentiometer Adaptation Values • 65 Potentiometer Range / Status • 66 Cruise Control System • 67 Cruise Control Shut-Off • 68 Transmission Range / Torque Conversion • 69 Air / Ride Spring Status • 70 Fuel Tank Venting / Valve Testing • 71 Fuel Tank Leak Test • 72 Fuel Tank Leak Test 2 • 73 Fuel Tank Venting / Mixture • 74 EGR Regulator Solenoid Adaptation

• 75 EGR Short Trip • 76 EGR Pressure Systems / Air Mass System • 77 Test Secondary Air Injection System - Bank 1 • 78 Test Secondary Air Injection System - Bank 2 • 79 Exhaust Flap - Banks 1 & 2 • 80 Advanced Control Module Identification I (Manufacture Date) • 81 Advanced Control Module Identification II (VIN & Immobilizer ID) • 82 Advanced Control Module Identification III (Flash Data) • 83 Advanced Control Module Identification III (First VIN) • 85 Mileage / Ignition Cycle Count • 86 Readiness Code I • 87 Readiness Code II • 88 Readiness Code III • 89 Distance Driven with MIL On • 90 Continuous Camshaft Adjustment - Bank 1 - Exhaust • 91 Continuous Camshaft Adjustment - Bank 1 - Intake • 92 Continuous Camshaft Adjustment - Bank 2 - Intake • 93 Continuous Camshaft Adaption Values • 94 Continuous Camshaft Adjustment - Banks 1 & 2 - Intake • 95 Performance Increase - Intake Manifold Change Over • 96 Continuous Camshaft Adjustment - Banks 1 & 2 - Exhaust • 97 Performance Increase - Intake Air Change Over / Snow Flap • 98 Continuous Camshaft Adjustment - Bank 2 - Exhaust • 99 Lambda Control Shut-Off - Basic Setting

100 Readiness Code (Older Systems) • 101 Fuel Injection • 102 Fuel Injection • 103 Air-Shrouded Fuel Injectors • 104 Start Adaptation Values • 105 Cylinder Shut-Off • 106 Fuel Pump Status / Shut-Off Time • 107 Lambda Regulation - Banks 1 & 2 • 110 Load / Full Throttle Enrichment • 111 Boost Pressure Control • 112 Exhaust Gas Temperature • 113 Load / Full Throttle Enrichment - Last Check • 114 Boost Pressure Control (%) • 115 Boost Pressure Control (mBar) • 116 Boost Pressure Control - Correction • 117 Boost Pressure Control - Pedal Pos. / Throttle Angle • 118 Boost Pressure Control - Temperature / Pressure • 119 Boost Pressure Control - Control Valve Status • 120 Traction Control - ASR / FDR • 122 Transmission • 123 Reserved For CAN-Bus Signals • 124 Reserved For CAN-Bus Signals • 125 CAN-Databus Powertrain Communication (Modules … • 126 CAN-Databus Powertrain Communication (Modules …

• 127 CAN-Databus Powertrain Communication (Modules 22 / 34 / 16) • 128 Reserved For CAN-Bus Signals • 129 Reserved For CAN-Bus Signals • 130 Map Cooling - Coolant Filling • 131 Map Cooling - Temperatures • 132 Map Cooling - Status • 133 Coolant Fan Configuration • 134 Temperatures • 135 Coolant Fan Control • 136 Relay for Coolant Fan Actuation • 137 Air Condition Requirements • 138 Air Mass - Average / Vehicle Speed • 139 Air Mass - Actual / Specified • 140 Pressure Control Valve • 141 Fuel Supply System • 142 Throttle Position Range / Status • 143 Charge Movement Flap Opening / Status • 144 Charge Movement Flap Actual / Specified • 145 Exhaust Gas Temperature Sensor • 146 Exhaust / Catalytic Converter Status • 147 Charge Movement Flap For BDE • 148 Catalytic Converter Status • 160 Cylinder Recognition / Control - Cylinder 1-4 • 161 Cylinder Recognition / Control - Cylinder 5-8

• 162 Lambda Control - Delta Lambda - Specified / Actual • … • 166 O2 Bank 1 Status • 167 Deceleration Calculation / Thrust Count • 168 Potentiometer Range / Status • 169 Turbo Bypass / Status • 170 Starter Voltage / Relay Status • 171 Clutch Switch • 199 Temperatures - Status (Cats/Coolant) • 200 Readiness Code - Status • 201 O2 Dwell / Range • 204 Manifold Pressure 205 • 208 Throttle Opening 209 • 220 Ground Current • 221 Coolant / Intake Temperature

+2

Andy from Lutherville-Timonium

 

Technician
 

Nice post Chris! Thanks for the info.

0

Dan from Bucuresti

 

Owner/Technician
 

Great info, thanks!

0

Eric from Chapel Hill

 

Mechanic
 

I notice that the information in 106 is different in the first three screens than the last. Is that beta v release version?

0

Chris from Commack

 

Diagnostician
 

This is from a different tool and vehicle. This wasn't a case study, merely just a tech tip. The data will be almost the same with a broken and fixed vehicle.

0