E020

ECM Code E020:

DFI Fuel Pump Circuit:

DESCRIPTION:

The ECM monitors voltage on the fuel pump power CKT 120 to detect fuel pump voltage supply faults. Code E020 is set when the ECM sees the fuel pump not energized (O VOLTS on the feedback) with the engine cranking or running. The code is designed to detect a fuel pump relay fault; relay not powering the fuel pump.

TEST CONDITIONS:

1. Engine speed greater than or equal to 24 RPM.

FAILURE CONDITIONS:

Fuel pump feedback voltage less than or equal to 2 volts for 3 seconds or more.

ACTION TAKEN:

1. Store code as current until engine is turned off.
2. ECM turns on "SERVICE ENGINE SOON" telltale.
3. ECM commands BCN4 to display "SERVICE CAR SOON" message on CCDIC.

NOTES ON FAULT TREE:

1. Engine starts with a current E020 indicates that the engine started with fuel pump powered through the oil pressure switch - the relay circuit may be at fault.

2. 0 volts with engine running indicates an open from the fuel pump power circuit to ECM - the fuel pump relay is not at fault.

3. Testing for ECM's ability to energize relay coil.

4. Testing for open from 1OA fuel pump fuse to relay pin "1".

5. Testing for open from relay pin "2" to ground.

6. If light turns on then all relay circuitry is OK. Fault causing the code must be the relay.

7. Fault is most likely at the ECM connector or ECM. Before replacing the ECM, perform "ECM Replacement Check", CHART C-1.

NOTE ON INTERMITTENTS:

If intermittent code E020 is stored, unplug the oil pressure switch, start engine and allow to idle. Manipulate affected wiring, ensure that the ECM J2 (C/D) connector is latched, check the relay for proper installation into relay center socket. If the fault is induced, the engine will stall, code E020 will set. If code E020 sets without an engine stall, the cause is an intermittent open CKT 120A between ECM D9 and splice to 120B.
Review the snapshot data parameters stored with this code to verify failure condition. If the failure condition is verified, check and repair intermittent wiring connection, or sensor.

ECM Code E020 (Cont'd):

NOTES ON FAULT TREE:

1. At key "ON" light should be "OFF" or glow for 2 seconds as the relay powers up the fuel pump.

2. If a short is present, it is in CKT 120 the fuel pump or ECM. Normal CKT resistance is 3 to 4 ohms.

3. Checking for ECM shorting 120A to ground.

4. Checking for short internal to fuel tank.

5. Check fuel pump for shorts, check sender harness and check RFI supression connector.

6. Checking for CKT 120 shorted to ground.

7. Check for grounded fuel pump test point, then connection at relay center, oil pressure switch, then diagnose for harness shorted to ground.

8. If the light is on steadily then the non switched portion of the fuel pump circuit is shorted-checking circuit 239.

NOTE ON INTERMITTENTS:

If the fuel pump test point is grounded (for example if the test point is mistakenly grounded instead of the generator disable connector) the fuse will blow and E020 will set.

Replace fuse, start engine and allow to idle. Manipulate affected wiring and connectors. If fault occurs, the fuse will blow and the engine will stall.