Failure of the PHC 1

TASK 30-31-00-810-862-A
Failure of the PHC 1

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
ASM 303101
AMM 30-31-34-000-002	Removal of the Probe Heat Computer (PHC)
AMM 30-31-34-400-002	Installation of the Probe Heat Computer (PHC)
AMM 34-12-34-000-001	Removal of the ADIRU
AMM 34-12-34-400-001	Installation of the ADIRU
ASM 341302

3. Fault Confirmation
Subtask 30-31-00-860-051-A

A. Test
(1) If the fault occurs at each engine start or each engine shutdown:

(2) If the fault occurs in other conditions:

4. Fault Isolation
Subtask 30-31-00-810-114-A

A. Do the step that follow:

Subtask 30-31-00-810-138-B

B. Do the steps that follow:

(1) If the wiring is not correct:

(2) If the wiring is correct:

(a) If there is a ground signal:

(b) If there is no ground signal:

Connect electrical connector A to PHC1.
Replace the RELAY-OIL LOW PRESS AND GROUND, ENG 1 [12KS1] and the RELAY-OIL LOW PRESS AND GROUND, ENG 2 [12KS2] .

1 If the fault continues:

Disconnect electrical connector A from PHC1.
Do a check and repair the wiring from:
PHC1 (6DA1) pin A/f to engine 1 oil low pressure and ground relay (12KS1) pin A/4
Engine 1 oil low pressure and ground relay (12KS1) pin A/A to the ground
PHC1 (6DA1) pin A/g to engine 2 oil low pressure and ground relay (12KS2) pin A/4, and
Engine 2 oil low pressure and ground relay (12KS2) pin A/A to the ground
ASM 303101.

[Rev.8 from Aug 2018] 2026.04.04 04:29:39 UTC