So, lets assume that my oil pressure sensors are working.
03-31-2004, 03:35 PM
#1
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So, lets assume that my oil pressure sensors are working.
What would cause the light to come on? what causes this low oil pressure? How do I check/rule out these things????
03-31-2004, 03:51 PM
#2
From the Bentley manual...........
<center><img src="http://pictureposter.audiworld.com/6607/oilpswitchs.jpg"></center><p>checking (engine code AAH)
The oil pressure switch is located on the left side of the oil pan behind the oil filter (warning light and alarm).
For vehicles with an oil pressure gauge, the pressure sensor is an integral part of the switch (black connector).
A - 1.8 bar (26 psi) oil pressure switch (white connector)
B - 0.3 bar (approx. 4 psi) oil pressure switch (blue connector)
Test requirements
Oil level OK
Oil pressure warning light -K3- lights when ignition turned on
Mini Check/Auto-Check system indicates OK
Engine coolant temperature approx. 80Cor 176F (radiator coolant fan must have switched on at least once)
Checking oil pressure
- Remove 0.3 bar (4.35 psi) pressure switch.
- Install VAG 1342 oil pressure tester in place of oil pressure switch, but do not connect wiring.
- Start engine and let idle.
- Increase the engine speed to 2000 RPM.
Oil pressure must be 4.5-6.0 bar (65-87 psi)
Checking oil pressure switch
- Disconnect 1.8 bar (26 psi) oil pressure switch -A-.
- Switch ignition on.
- Connect VAG1527B voltage tester between:
1.8 bar switch -A- (white connector) and ground
0.3 bar switch -B- (blue connector) and ground
Black connector for oil pressure gauge sender and ground (where applicable)
In each case:
LED on tester must light or at least flicker
If LED on tester does not light:
- Determine cause of interruption using wiring diagrams, and repair or replace as necessary.
- Reconnect wires to oil pressure switch.
- Connect tester between 1.8 bar switch -A- and ground.
LED on voltage tester must light or flicker
- Connect tester between 0.3 bar switch -B- and ground.
LED on voltage tester must NOT light
- Start engine and let idle.
- Connect tester between the 1.8 bar switch -A- and ground.
LED on voltage tester must NOT light
- Connect tester between 0.3 bar switch -B- and ground.
LED on voltage tester must light
If any of these checks fail to produce the specified result:
- Replace oil pressure switch.
If you replace both switches, the relay is suspect.
The oil pressure switch is located on the left side of the oil pan behind the oil filter (warning light and alarm).
For vehicles with an oil pressure gauge, the pressure sensor is an integral part of the switch (black connector).
A - 1.8 bar (26 psi) oil pressure switch (white connector)
B - 0.3 bar (approx. 4 psi) oil pressure switch (blue connector)
Test requirements
Oil level OK
Oil pressure warning light -K3- lights when ignition turned on
Mini Check/Auto-Check system indicates OK
Engine coolant temperature approx. 80Cor 176F (radiator coolant fan must have switched on at least once)
Checking oil pressure
- Remove 0.3 bar (4.35 psi) pressure switch.
- Install VAG 1342 oil pressure tester in place of oil pressure switch, but do not connect wiring.
- Start engine and let idle.
- Increase the engine speed to 2000 RPM.
Oil pressure must be 4.5-6.0 bar (65-87 psi)
Checking oil pressure switch
- Disconnect 1.8 bar (26 psi) oil pressure switch -A-.
- Switch ignition on.
- Connect VAG1527B voltage tester between:
1.8 bar switch -A- (white connector) and ground
0.3 bar switch -B- (blue connector) and ground
Black connector for oil pressure gauge sender and ground (where applicable)
In each case:
LED on tester must light or at least flicker
If LED on tester does not light:
- Determine cause of interruption using wiring diagrams, and repair or replace as necessary.
- Reconnect wires to oil pressure switch.
- Connect tester between 1.8 bar switch -A- and ground.
LED on voltage tester must light or flicker
- Connect tester between 0.3 bar switch -B- and ground.
LED on voltage tester must NOT light
- Start engine and let idle.
- Connect tester between the 1.8 bar switch -A- and ground.
LED on voltage tester must NOT light
- Connect tester between 0.3 bar switch -B- and ground.
LED on voltage tester must light
If any of these checks fail to produce the specified result:
- Replace oil pressure switch.
If you replace both switches, the relay is suspect.
03-31-2004, 03:58 PM
#3
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I love the fact that the engine temp must be 80c for the test to work.
Nothing like running the engine up to operating temp with a suspected oil pressure problem!!
03-31-2004, 04:47 PM
#7
Actually.............
<center><img src="http://pictureposter.audiworld.com/6607/oilpress.jpg"></center><p>On the B4 90, its a chip inside the instrument cluster, which controls the signals from the oil pressure senders.
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03-31-2004, 04:56 PM
#8
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Thanks so much milk Tip but......
1st I cannot read that picture. Do you have a pic of this chip's location. I know you said the instrument cluster, but I would like to narrow it down a bit. Thanks again man.