E053

TEST CONDITIONS
1. RPM equal to or greater than 456;
2. Fuel pump feedback voltage less than or equal to 7 volts.

FAILURE CONDITIONS
No distributor reference pulses for 0.4 seconds.

ACTION TAKEN
1. Code EO53 is stored as a history code. (No telltales are illuminated).

DESCRIPTION
Code EO53 is set if the ECM does not receive distributor reference pulses from the HEI for more than 0.4 seconds. Since the PFI system requires HEI pulses in order to fire the injectors, most occurrences of Code EO53 will be accompanied by a stall.

Notes on Fault Tree
1. Checking for hard failure of distributor reference which will cause Code EO12 to set.
2. Do not diagnose Code EO53 unless the customer complains of stumble, miss, stall or other driveability condition that could be caused by loss of spark of fuel.
3. See "Description", above.

Notes on Intermittents
Code EO53 can be caused by:
- Loss of ground on CKT 453
- Loss of distributor reference signal on CKT 430
- Loss of battery power to "B+" terminal of the distributor.

Do not attempt to diagnose Code EO53 unless the customer Symptom is stumble, stall, miss or other driveability condition that could be caused by loss of spark or fuel.