Section 7
DIAGNOSTIC TESTS
2.If engine cranks in Step 3 when Wire 17 is grounded, but will not crank when the Switch is set to “START”, replace the Start- Stop Switch.
3.If the
4.If engine will not crank when Wire 17 is grounded, proceed as follows:
a.Use a jumper wire to connect the circuit board's Wire 17 (pin location
b.If engine cranks now, but would not crank in Step 3 of the procedure, check Wire 17 for con- tinuity between the circuit board and
5.For Problem 9 (Section 6), if switch tests GOOD, go to Test 30.
TEST 25 - CHECK POWER SUPPLY TO WIRE 56
DISCUSSION:
If battery voltage is available to the Engine Controller board in Test 23, then DC voltage should be delivered to Wire 56 when the
PROCEDURE:
1.Set a VOM to measure DC voltage (12 VDC).
2.Disconnect Wire 56 from its Starter Contactor Relay terminal.
3.Connect the meter positive (+) test lead to Wire 56, just discon- nected. Connect the other test lead to frame ground. No volt- age should be indicated.
4.Actuate the
5.Connect the VOM positive (+) test lead to Wire 56 (Pin Location
6.Actuate the
RESULTS:
1.If battery voltage was measured in Step 6, but not in Step 4, repair or replace Wire 56 between the Engine Controller Circuit Board and Starter Contactor Relay.
2.If battery voltage was not available in Step 6, replace the Engine Controller Circuit Board.
3.If battery voltage is available in Step 4 but engine does not crank, go to Test 26.
TEST 26- CHECK STARTER CONTACTOR
RELAY
DISCUSSION:
If battery voltage is available to Wire 56 but the engine won't crank, the possible cause could be a failed Starter Contactor Relay.
PROCEDURE:
1.Set the VOM to measure resistance (“R x 1” scale). Remove Wire 0 from the Starter Contactor Relay (SCR). Connect one meter test lead to Wire 0, and connect the other meter test lead to frame ground. “Continuity” should be measured. Reconnect Wire 0.
2.Set the VOM to measure resistance (“R x 1” scale). Disconnect Wire 16 and Wire 13 (Wire 13 is 12VDC isolate from ground) from the Starter Contactor Relay (SCR). Connect one meter test lead to an SCR terminal, and connect the other meter test lead to the remaining SCR terminal. “Infinity” should be mea- sured. Set the
Short to Ground:
3.Set the VOM to measure resistance (“R x 1” scale). Disconnect Wire 56 from the Starter Contactor Relay (SCR). Connect one meter test lead to the SCR terminal from which Wire 56 was just removed. Connect the other meter test lead to a clean frame ground. Starter Contactor Relay coil resistance of 155 ohms should be measured. If “Continuity” is measured a short to ground exists.
Note: Current draw of the Starter Contactor Relay coil at nominal voltage is approximately 80ma.
Figure 7-19. – Starter Contactor Relay
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