Suburban 3/4 Ton 4WD V8-305 5.0L (1986)
5.
If resistance is not as specified, disconnect electrical connector from knock sensor and measure resistance between sensor terminal and ground. If
resistance is 98-99 ohms, repair wiring between knock sensor and controller. If resistance is not 98-99 Kohms, knock sensor is defective.
6.
Reconnect 10 pin connector to controller and measure voltage between pins F and K with ignition on. If voltage reading is less than 11.6 volts
repair feed circuit as needed.
7.
Set voltmeter on 20 volt AC scale and measure voltage between connector pins H and K with ignition on. If reading is less than .20 volt, inspect
system wiring and repair as needed. If reading is greater than .20 volt, ensure all connectors are properly seated, then road test vehicle. If problem
persists, replace ESC controller.
Engine Detonation
1.
Inspect connector and wiring to knock sensor and repair as needed.
2.
Connect suitable spark advance tester to engine, run engine until it reaches normal operating temperature and set engine to run at a minimum of
1200 RPM, then observe ignition timing while tapping on exhaust manifold. If ignition timing retards when manifold is tapped, ESC system is
operating properly.
3.
Stop engine, disconnect 10 pin connector from ESC controller and measure resistance between pins B and K of connector. If resistance is not
98-99 ohms, proceed to step 5.
4.
Measure resistance between pins H and K in connector. If resistance is 14-16 ohms, replace controller. If resistance is not 14-16 ohms, repair
wiring to controller.
5.
Disconnect electrical connector from knock sensor and measure voltage at sensor terminal with engine running at 2000 RPM. If reading is not .08
volt or more, knock sensor is defective.
6.
Stop engine. If knock sensor voltage output is satisfactory, check wiring between knock sensor and terminal B of controller and between controller
terminal K and ground and repair as needed.
