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Bulletin No.: PIT5510C
Published date: 07/21/2017

Preliminary Information

PIT5510C Fuel Gauge Displays Empty / Low Fuel Light On / DTC P2636

Models

Brand:	Model:	Model Years:	VIN:		Engine:	Transmissions:
			from	to
Chevrolet	Silverado 3500 Chassis Cab	2016	All	All	6.6L LML	All
GMC	Sierra 3500 Chassis Cab	2016	All	All	6.6L LML	All

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

With Dual Fuel Tanks RPO N2N

Supersession Statement:

This PI was superseded to add a Diagnostic Tip to inspect the new fuel transfer line for being kinked, which can cause a repeat P2636. Please discard PIT5510B.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition / Concern

Note:  See “Diagnostic Tip” at the bottom of the recommendation section to prevent a repeat P2636 from occurring.

Some owners may comment that the fuel gauge shows empty and the low fuel level indicator is on.  When checking for DTCs, a P2636 will be set in the ECM.

Recommendations / Instructions

Note:  See “Diagnostic Tip” at the bottom of the recommendation section to prevent a repeat P2636 from occurring.

Important: The vehicle SHOULD NOT be refueled while the engine is running or with the ignition on, as this can cause a false P2636 to set.  ALWAYS turn vehicle off prior to refueling.

If Chassis Up-fit bed or body is easily removed, remove to access top of Front Fuel Tank.

1. If Chassis Up-fit bed or body cannot be easily removed, remove the FRONT fuel tank. Refer to Fuel Tank Replacement (Cab/Chassis – Front) Doc Id # 2456119.

2. With the front tank removed, install cap from line kit onto rear balance pump inlet port on front tank (1) Refer to Plastic Collar Quick Connect Fitting Service. Doc Id# 2147646.

3. Measure the Fuel Tank Fill Vent hose 5 ½” from the end at the fuel pump module and cut with hose cutters as seen below (2).

4. On the other side, from the cut, measure back an additional 5/8″ and cut the 5/8″ section off and discard as seen below (3).

5. Connect the supplied hose, from the fuel transfer line kit part number 84214102, with the side of the “Y” facing toward the tank as seen below (4). Secure using the supplied hose clamps (5) and torque to (2.5N-m; 22 lb-in.).

NOTE:  Before installing the new fuel transfer line kit, see the diagnostic tip below for inspecting the line for any kinks.  A kinked line could occur during installation/shipping/etc. and will restrict fuel flow, causing a repeat P2636.

6. It is important to route the Vent Hose over the TOP of the fill hose as seen below (6) to prevent pudding of fuel in the line.

7. Remove the original fuel balance pump line from the pump tube (7) Refer to Plastic Collar Quick Connect Fitting Service. Doc Id# 2147646 and cross member (8) as seen below.

8. Remove plastic clip (9) seen below from fuel balance pump line and place clip back into hole in cross member.

9. Re-Install front fuel tank into vehicle being careful not to kink line and to route new line above cross member. Refer to Fuel Tank Replacement (Cab/Chassis – Front) Doc Id # 2456119.

10. Connect quick-connect end of new line to fuel balance pump line as seen below (10) Refer to Plastic Collar Quick Connect Fitting Service. Doc Id# 2147646.

11. Use supplied zip tie to secure new supplied line to the clip on the cross member as seen below (11). Trim off excess from zip tie once secured.

12. Start the vehicle and check for fuel leaks.
13. Connect Scan Tool and clear any DTC’s. Next, command the fuel transfer pump on and re-check for fuel leaks while transfer pump is running.
14. New ECM calibrations have been released for further improvement, but will NOT be released in Tis2Web. To obtain the new ECM calibration, please contact Techline Customer Support Center (TCSC) @ 1-800-828-6860 and request the new ECM calibrations to address DTC P2636.  Reprogram the ECM with the updated calibration from TCSC.

NOTE:  If this PI was performed before the ECM calibrations were available and the vehicle has returned with DTC P2636, complete step 14.

Diagnostic Tip-

During installation of the new fuel transfer line kit, or if a vehicle returns with a P2636 after the new fuel line kit and ECM calibration has been completed, inspect the new fuel transfer line for being kinked (2), as shown below.  Because the line is covered with a conduit (1) it will be necessary to remove any zip ties and slide the conduit back to inspect the fuel transfer line for any kinks.  If the line is kinked, it will restrict the fuel flow and cause a P2636 to set.  Replace the fuel transfer line kit if the line is kinked.

Parts Information

Warranty Information

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

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