No Start, Rough Idle or Erratic Injector Balance Rates - keywords 6.6 crank cut DTC fuel hesitate high LB7 LLY P0300 P0301 P0302 P0303 P0304 P0305 P0306 P0307 P0308 P0335 P0336 sensor SES shift
| Subject: | No Start, Rough Idle or Erratic Injector Balance Rates |
| Models: | 2001-2005 Chevrolet Kodiak, Silverado |
| 2001-2005 GMC Sierra, Topkick |
| Equipped with the 6.6L Diesel Engine (VIN 1 or 2 - RPO LB7 or LLY) |
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
The customer concern will be described as a rough idle, SES light, unstable idle, no start, hesitation, surge or stalling. The vehicle may have misfire DTCs and/or crank sensor DTCs.
Recommendation/Instructions:
Complete current SI diagnostics for any duplicated symptoms or DTCs set. If diagnostics are inconclusive, monitor the injector balance rates. If the injector balance rates are high, erratic, or fluctuating on random cylinders (not staying on one specific cylinder), check for a loose crankshaft sensor reluctor.
If the vehicle is a no start and the current SI diagnostics for Engine Cranks but Does Not Run are inconclusive, Inspect for a loose crankshaft sensor reluctor.
To inspect the crankshaft sensor reluctor, remove the right inner fender, the crank sensor, and the crank sensor spacer. Use a blunt probe and try to move reluctor clockwise or counter clockwise. If the crankshaft reluctor is found loose, repair by it replacing any necessary parts. Be sure to install new crank reluctor to oil pump drive gear (knock pins) alignment pins. See SI repair instructions for Crankshaft Reluctor and Oil Pump Drive Gear Replacement.
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.
