Checking the Fuel Pump (FP)

Fuel Pump
- Ignition off.
- Remove fuse 2.
- Connect an ammeter between fuse 2 terminals on fuse holder.
- Ignition on.
- Activate fuel pump (FP).
- When the fuel pump is operating power consumption should be 4 - 5 Amps.

If reading is OK:
^ Refer to: Checking Ignition Spark section.

If reading is incorrect:
^ Proceed to test step below.





Starting Fuel Pump
- Ignition off.
- Remove electrical distribution unit cover.
- Remove the fuel pump relay (pos. 103 in the electrical distribution unit).
- Ammeter connected at fuse 2.
- Ignition on.
- Connect a cable between relay base terminals 1 and 3.
- When the fuel pump is operating power consumption should be 4 - 5 Amps.

If reading is OK:
^ Proceed to Checking Fuel Pump Relay Ground Lead section below.

If reading is incorrect:
^ Proceed to test step below.





Checking The Voltage Supply To The Relay
- Install fuse 2.
- Ignition on.
- Fuel pump relay removed.
- Connect a voltmeter between relay base terminal 1 and ground.
- The voltmeter should read battery voltage.

If reading is OK:
^ Proceed to test step below.

If reading is incorrect:
^ Check fuse 2. Replace fuse if necessary. If the fuse is OK: Check cable between fuel pump relay terminal 1 and fuse 2 for an open-circuit.





Checking Fuel Pump Ground Lead
- Ignition off.
- Open two-pin fuel pump connector (C/BA) in the trunk.
- Connect an ohmmeter between fuel pump connector terminal 2 (fuel pump relay side) and ground.
- The ohmmeter should read approx. 0 ohms.

If reading is OK:
^ Proceed to Checking The Fuel Pump section below.

If reading is incorrect:
^ Proceed to test step below.





Checking Fuel Pump Ground Terminal
- Ignition off.
- Fuel pump disconnected (connector C/BA).
- Check fuel pump ground terminal (31/48) for contact resistance and oxidation.
- Connect an ohmmeter between fuel pump connector terminal 2 (fuel pump relay side) and ground.
- The ohmmeter should read approx. 0 ohms.

If reading is OK:
^ The cause of the fault has been poor contact in the fuel pump ground terminal.

If reading is incorrect:
^ Check cable between fuel pump terminal 2 and ground terminal (31/48) for an open-circuit.





Checking The Fuel Pump
- Ignition off.
- Fuel pump disconnected (connector C/BA).
- Connect an ohmmeter between fuel pump connector terminals 1 and 2 (fuel pump side).
- The ohmmeter should read 0.5 - 2.0 ohms.

If reading is OK:
^ Check cable between fuel pump relay terminal 3 and fuel pump terminal 1 for an open-circuit.

If reading is Incorrect:
^ Try a new fuel pump.





Checking Fuel Pump Relay Ground Lead
- Ignition off.
- Fuel pump relay removed.
- Connect an ohmmeter between relay base terminal 2 and ground.
- The ohmmeter should read approx. 0 ohms.

If reading is OK:
^ Proceed to Checking Signal Cable Voltage section below.

If reading is incorrect:
^ Proceed to test step below.





Checking Fuel Pump Relay Ground Terminal
- Ignition off.
- Fuel pump relay removed.
- Check fuel pump relay ground terminal (31/51) for contact resistance or oxidation and remedy.
- Connect an ohmmeter between relay base terminal 2 and ground.
- The ohmmeter should read approx. 0 ohms.

If reading is OK:
^ The cause of the fault has been poor contact in the fuel pump relay ground terminal.

If reading is incorrect:
^ Check cable between fuel pump relay terminal 2 and ground terminal (31/51) for an open-circuit.





Checking Signal Cable Voltage
- Ignition on.
- Fuel pump relay removed.
- Connect a voltmeter between relay base terminal 4 and ground.
- The voltmeter should read 4 - 5 Volts.

If reading is OK:
^ Proceed to Checking The Connector section below.

If value is lower:
^ Proceed to test step below.

If value is higher:
^ Check cable between fuel pump relay terminal 4 and engine control module (ECM) # B27 for a short-circuit to supply voltage.





Checking Signal Cable Resistance To Ground
- Ignition off.
- Wait approx. 150 seconds.
- Fuel pump relay removed.
- Disconnect engine control module.
- Connect an ohmmeter between relay base terminal 4 and ground.
- The ohmmeter should read infinite resistance.

If reading is OK:
^ Check cable between fuel pump relay terminal 4 and engine control module # B27 for an open-circuit.

If reading is incorrect:
^ Check cable between relay base terminal 4 and engine control module # B27 for a short-circuit to ground.





Checking The Connector
- Ignition off.
- Reinstall fuel pump relay.
- Connect the engine control module and fuel pump.
- Try to start the engine.
- Does the engine start?

Yes:
^ The cause of the fault has been poor contact in the engine control module, fuel pump relay or fuel pump connectors. Check connectors for contact resistance or oxidation and remedy.

No:
^ Try a new fuel pump relay.