Engine Oil Pressure Gage Inaccurate or Inoperative (6.6L (LB7) Engine)

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Step	Action	Value(s)	Yes	No
Schematic Reference: Instrument Cluster Schematics Connector End View Reference: Master Electrical Component List
1	Did you perform the Instrument Cluster Diagnostic System Check?	-	Go to Step 2	Go to Diagnostic System Check - Instrument Cluster
2	Start the engine. Does the engine oil pressure (EOP) gage display within the specified range?	207-483 kPa (30-70 psi)	Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems	Go to Step 3
3	Install a scan tool. Turn ON the ignition, with the engine OFF. With a scan tool, perform the Displays Test in the instrument panel cluster (IPC) scan tool Output Controls. Does the engine oil pressure gage move up and down when commanded?	-	Go to Step 4	Go to Step 14
4	Turn OFF the ignition. Disconnect the engine oil pressure (EOP) sensor. Measure the resistance at the EOP sensor between the EOP sensor signal circuit pin and the 5-volt reference circuit pin. Measure the resistance at the EOP sensor between the 5-volt reference circuit pin and the low reference circuit pin. Are both of the resistance values within the specified range?	6k-16k ohms	Go to Step 5	Go to Step 10
5	Measure the voltage between the 5-volt reference circuit of the EOP sensor and the low reference circuit of the EOP sensor Does the voltage measure greater than the specified value?	4.6V	Go to Step 9	Go to Step 6
6	Test the EOP 5-volt reference circuit for a for an open, for a short to ground, or for a high resistance. Refer to Circuit Testing and toWiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 15	Go to Step 7
7	Disconnect the negative battery cable. Measure the resistance from the low reference circuit of the EOP sensor to a good ground. Does the resistance measure less than the specified value?	5 Ω	Go to Step 11	Go to Step 8
8	Test the EOP low reference circuit for high resistance or for an open. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 15	Go to Step 11
9	Test the EOP oil pressure sensor signal circuit for a for an open, for a short to ground, or for a high resistance. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 15	Go to Step 11
10	Inspect for poor connections at the harness connector of the EOP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 15	Go to Step 12
11	Inspect for poor connections at the harness connector of the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition?	-	Go to Step 15	Go to Step 13
12	Replace the engine oil pressure sensor. Refer to Engine Oil Pressure Sensor and/or Switch Replacement in Engine Mechanical - 6.6L. Did you complete the replacement?	-	Go to Step 15	-
13	IMPORTANT: Program the replacement ECM. Replace the ECM. Refer to Engine Control Module (ECM) Replacement in Engine Controls - 6.6LDid you complete the replacement?	-	Go to Step 15	-
14	Replace the IPC. Refer to Instrument Panel Cluster (IPC) Replacement . Did you complete the replacement?	-	Go to Step 15	-
15	Operate the system in order to verify the repair. Did you correct the condition?	-	System OK	Go to Step 2