Sany Excavator Fault Code P136: Complete Diagnostic Guide

What is Sany Excavator Fault Code P136?

Fault Code P136 indicates a cylinder #6 glow plug circuit malfunction or open circuit in Sany excavators equipped with diesel engines. This code triggers when the Electronic Control Module (ECM) detects abnormal resistance, voltage drop, or complete failure in the glow plug circuit for the sixth cylinder during pre-heating or operation.

The glow plug system is critical for cold-start performance in diesel engines. When cylinder #6's glow plug fails to heat properly, it can cause incomplete combustion, rough idling, and increased white smoke during startup. In Sany machines, this fault is particularly important because the ECM monitors each glow plug individually to ensure optimal combustion chamber temperatures, especially in cold weather conditions.

Common Symptoms

When Code P136 is active on your Sany excavator, you may experience:

• Hard starting or extended cranking time, especially in cold temperatures below 40°F (4°C)
• Excessive white or gray smoke from the exhaust during initial startup that persists longer than normal
• Rough engine idle for the first few minutes after starting, with noticeable vibration
• Check Engine Light (CEL) or glow plug indicator remaining illuminated on the dashboard
• Reduced engine power during warm-up phase, with hesitation under load

Potential Causes

The most common technical reasons for P136 on used Sany excavators include:

• Failed glow plug element in cylinder #6 due to carbon buildup or internal element burnout (common after 3,000+ operating hours)
• Damaged wiring harness or corroded connectors between the glow plug relay and cylinder #6, often caused by heat exposure or vibration
• Faulty glow plug relay or control module unable to supply proper voltage (typically 11-12V) to the circuit
• Open circuit caused by broken wire strands in the harness, particularly at flex points near the engine mount
• ECM internal fault in the glow plug driver circuit (rare, but possible in older machines)

How to Troubleshoot and Fix Code P136

Step 1: Visual Inspection Begin by inspecting the wiring harness running to cylinder #6's glow plug. On used excavators, check for chafing against the engine block, heat damage near the exhaust manifold, or corrosion at the connector terminals. Clean any corroded connections with electrical contact cleaner and dielectric grease.

Step 2: Glow Plug Resistance Test Disconnect the electrical connector from the #6 glow plug. Using a digital multimeter, measure resistance between the glow plug terminal and engine ground. A healthy glow plug should read 0.5-2.0 ohms. Readings above 5 ohms or infinite resistance indicate a failed glow plug requiring replacement.

Step 3: Circuit Voltage Test Reconnect the harness and measure voltage at the glow plug connector during the pre-heat cycle (key on, engine off). You should see 10.5-12.5V for 15-30 seconds. No voltage indicates a problem with the glow plug relay, fuse, or ECM output. Check the relay operation and replace if clicking but not passing voltage.

Step 4: Harness Continuity Check If the glow plug tests good but voltage is absent, trace the wire back to the relay/control module. Test continuity through the entire circuit. In used machines, pay special attention to wire insulation deterioration and connector pin corrosion—common failure points after 5+ years of operation.

Step 5: Component Replacement Replace the faulty glow plug with OEM or equivalent parts rated for your specific Sany engine model. Always apply anti-seize compound to threads and torque to manufacturer specifications (typically 15-20 Nm). Clear codes using Sany diagnostic software or a compatible scan tool and verify repair with a cold-start test.

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Disclaimer: This guide provides general troubleshooting information for Code P136. Always consult your Sany service manual for model-specific procedures and torque specifications. If you're unfamiliar with diesel engine electrical systems, consult a certified heavy equipment technician to avoid damage to the ECM or engine components.