Chart 1

Diagnostic Chart:

Wiring Diagram:

In order to diagnose this system, battery voltage must be above 11 volts. Cranking speed of the starter must be normal and fuel quality and quantity should be checked. When ignition is On and crank pulses are received, IC pulses are delivered to the EI module. Also pulses are delivered to the injectors when crank pulses are received.

DIAGNOSTIC AIDS
Water in the fuel can cause a no start during cold weather starts.

An ECT sensor reading incorrectly can cause a no start or a hard start. This may be due to over-fueling or under-fueling.

ECT may be compared to IAT temperature with scan tool if engine has cooled overnight at ambient temperature. They should be within four degrees of each other with ignition On and key Off.

If the MAP sensor five volt line is shorted to ground, a DTC 1635 will set. Diagnose this DTC first.

TEST DESCRIPTIONS
1. If an injector fuse is blown, all four injector DTCs will set when the ignition is turned On.
2. If the five volt reference circuit becomes shorted to ground it will result in a no start.
3. An IC fault will cause two mating cylinders to not spark and may result in a no start especially if the engine is cold.
4. An EGR stuck open may result in a no start.
5. If no rpm is indicated spark and injectors will not be turned On. (No 7x signal to the PCM from the CKP sensor.)
6. Under normal cranking conditions the 7x counter should count up to 14 (two cranking revolutions) and reset to zero when a cylinder #4 signal is received.
7. Check for a flooded engine (fouled plugs).

If the MAP sensor five volt line is shorted to ground, a DTC 1635 will set. Diagnose this DTC first.

IMPORTANT: Always check fuses first in the IPJB and the UHJB.