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Example: If the engine is 90 deg.C. the instruments NTC should read about 115 ohms and the engine NTC should read about 250 ohms.

Page last updated:09/25/2004

Temporary EGR fix

Actually it's not a fix, it's just a way to be able to drive without a functioning EGR. Sometimes the EGR gets stuck or one of the related components fail and the ECU decides that you should limp home. This will happen at a moment you really need your car...

Before going on: Driving without a functioning EGR will increase the NOx output, which is an environment issue. In some countries this may be illegal. So before you decide to use this fix, check if you legally can do so.

How is it connected

The output wire of the MAF (pin 5 of Bosch MAF and pin 6 of Pierburg MAF) is cut and the circuit below is inserted. The wire coming from the MAF connects to the wire with label 'MAF Output' and the wire that goes to the ECU is connected to the wire 'To ECU'. The supply voltages of this circuit are taken from the MAF connector too. It only draws a current of a few mA. One more wire is connected to the EGR. Wire colors may differ, but it mostly is red/yellow. The other wire (black/yellow) of the EGR is connected to the infamous relay 109, it's the 12V supply. This circuit doesn't need this black/yellow wire. The flip switch X1 is set to the upper position to enable the circuit. If the circuit is enabled, the EGR valve should stay closed. If it is stuck open, close it by hand and plug the vacuum hose so it doesn't open again. Do not disconnect the EGR wires, the ECU will again force limp mode. If the EGR coil is burned, connect a 100 ohm 2W resistor across the EGR wires. The lower switch position is used to return to normal operation.

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