Central Control Module (CCM)

Circuit Description

The PASS-Key(R) fuel enable circuit is powered by 5 volts from the ECM, and is completed (grounded) by the CCM if all PASS-Key(R) requirements are met. When the ECM fuel enable signal input line senses that the CCM has grounded the circuit (senses a high-to-low transition), the ECM enables the fuel injectors so fuel can be delivered to the engine.

Code 54 will set if the fuel enable acknowledgment signal from the ECM (through serial data) indicates that the ECM has not detected the fuel enable signal when PASS-Key(R) is requesting fuel enable. Because the ECM sends serial data only with the ignition "ON," a Code 54 condition will only be recognized with the ignition "ON." Also, if serial data from the ECM is not being received by the CCM (CCM Code 41), Code 54 will not set, even though the fault is present, due to a lack of communications.

Test Description

Number(s) below refer to circled number(s) on the diagnostic chart.

1. This test checks to see if the ECM is putting out 5 volts up to the harness interconnect. If 5 volts is not found and the CKT 229 wiring and connectors are good, the ECM is faulty and should be replaced.
2. This test checks to see if the CCM is active on CKT 229 and if the wiring and connectors are good up to the harness interconnect.
3. This test checks to see if a fault indicated in Test 2 is in the wiring, connectors, PASS-Key(R), or the CCM.
4. This test checks to see if a fault indicated in Test 3 is due to PASS-Key(R), a poor connection at the CCM, or the CCM itself.

Diagnostic Aids

If the code is a history code, the problem may be intermittent. Try performing the tests shown while "wiggling" wiring and connectors; this can often cause the fault to appear. Check for poor connections at the CCM, the ECM, and at the I/P Harness-to-Engine. Harness interconnect; these could cause an open or an intermittent fault. Refer to "Intermittents/Poor Connections".

It is possible that a blown AIR BAG fuse or a disconnected DERM-to-I/P harness connector could cause a Code 54. The ECM receives its power through the AIR BAG fuse and DERM-to-I/P harness connection, so if the harness connector was disconnected or had poor connections, or the AIRBAG fuse was blown, the ECM would not be able to send a "fuel enabled" signal to the CCM, causing a Code 54. A disconnected DERM-to-I/P harness connector or blown AIR BAG fuse would also be indicated by all ECM functions being inoperative, since the ECM would have no power.

If there is a short to battery, a short to ground, or an open in CKT 229, the vehicle will exhibit a cranks-but-will-not-run condition.

If this code is set, it is very likely that ECM Code 46 will also be set.

The Fuel Enable Circuit is only sampled on initial start-up. If a failure in the circuit occurs while the vehicle is running, it will continue to run, but the vehicle will not start on the next start attempt, and this code will set.