DTC P0327 - KNOCK SENSOR (KS) CIRCUIT Isuzu Trooper II

Note. If an engine knock can be heard, repair engine mechanical problem before proceeding with circuit test.

Diagnostic Aids

If DTC cannot be duplicated, check scan tool FAILURE RECORDS to determine mileage since last DTC was set.

1. Perform On-Board Diagnostic (OBD) System Check. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
2. Operate vehicle under conditions to allow DTC to set. Using scan tool, monitor SPECIFIC DTC parameter until DTC P0327 test runs. If scan tool indicates DTC P0327, go to step 4). If DTC P0327 is not set, go to next step.
3. With ignition on and engine off, review and record FAILURE RECORDS for DTC P0327. Operate vehicle within FAILURE RECORDS conditions. Using scan tool, monitor SPECIFIC DTC parameter until DTC P0327 test runs. If scan tool indicates DTC P0327, go to next step. If DTC P0327 is not set, check for an intermittent problem, see «DIAGNOSTIC AIDS»(ref-16268-S08128872142001010800000) .
4. Check for damaged terminal at KS harness connector. Repair as necessary. Retest system. If KS harness connector is okay, go to next step.
5. Using a test light connected to battery positive terminal, probe KS harness connector Black/Blue wire (PCM side). If test light comes on, go to next step. If test light does not come on, repair open ground circuit. Retest system.
6. Ensure ignition is off. Disconnect PCM harness connectors. Check KS signal circuit for poor connection at PCM. Repair as necessary. Retest system. If connections are okay, go to next step.
7. Using a DVOM, check KS signal circuit between PCM and KS connector for an open, short to voltage or short to ground. Repair as necessary. Retest system. If wire is okay, go to next step.
8. Reconnect KS harness connector. Using an ohmmeter, measure resistance of KS between signal circuit at PCM harness connector and engine block. If resistance is 100 k/ohms, go to next step. If resistance is not as specified, replace KS. Retest system.
9. Connect a voltmeter between ground and KS signal circuit at PCM harness connector. Set to AC volts. Measure voltage produced by KS while tapping on engine lift bracket. If an AC voltage is produced, replace PCM. If no voltage is produced, replace KS. Retest system.

An intermittent may be caused by a poor connection, rubbed through wire insulation or a broken wire inside insulation. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. Connect voltmeter 58X reference circuit and wiggle harness and connectors. A change in voltage will indicate area of problem. If DTC cannot be duplicated, check scan tool FAILURE RECORDS to determine mileage since last DTC was set.

1. Perform On-Board Diagnostic (OBD) System Check. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
2. Attempt to start engine. If engine starts and runs, go to next step. If engine does not start and run, see «BASIC TESTING»(ref-16258) article.
3. Using scan tool, clear DTC P0336. Start engine and allow it to idle for one minute. Read DTCs. If DTC P0336 resets, go to next step. If DTC does not reset, check for an intermittent problem, see «DIAGNOSTIC AIDS»(ref-16268-S36337151282001010800000) .
4. Disconnect PCM and CMP sensor harness connectors. Check for an open or short to ground in 58X reference circuit between CKP sensor connector and PCM harness connector. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
5. Reconnect PCM and CKP sensor harness connectors. Using a voltmeter, measure voltage on 58X reference circuit at PCM harness connector while cranking engine. If reading is about 2.5 volts, go tostep 7). If voltage is not as specified, go to next step.
6. Check for faulty connections at CKP sensor. If a faulty connection is found, repair as necessary. If connections are okay, replace CKP sensor. Retest system.
7. Check for faulty connections at PCM. If a faulty connection is found, repair as necessary. If connections are okay, replace PCM. Retest system.

An intermittent may be caused by a poor connection, rubbed through wire insulation or a broken wire inside insulation. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. Connect voltmeter 58X reference circuit and wiggle harness and connectors. A change in voltage will indicate area of problem. If DTC cannot be duplicated, check scan tool FAILURE RECORDS to determine mileage since last DTC was set.

1. Perform On-Board Diagnostic (OBD) System Check. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
2. Attempt to start engine. If engine starts and runs, go to next step. If engine does not start and run, see «BASIC TESTING»(ref-16258) article.
3. Using scan tool, clear DTC P0337. Start engine and allow it to idle for one minute. Read DTCs. If DTC P0337 resets, go to next step. If DTC does not reset, check for an intermittent problem, see «DIAGNOSTIC AIDS»(ref-16268-S28879138012001010800000) .
4. Turn ignition off and disconnect CKP sensor. Turn ignition on. Connect a voltmeter between 5-volt reference and sensor ground terminals at harness connector. If reading is 4-6 volts, go to step 7). If reading is not as specified, go to next step.
5. Using a voltmeter, backprobe between PCM harness connector 5-volt reference circuit and ground terminals. If reading is 4-6 volts, go to next step. If reading is not as specified, go to step 10).
6. Check CKP sensor 5-volt reference circuit and ground circuit between CKP sensor and PCM for an open, short to ground or short to power. Repair as necessary. Retest system.
7. Turn ignition off and disconnect PCM and CKP sensor harness connectors. Check for an open or short to ground in 58X reference circuit between CKP sensor connector and PCM harness connector. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
8. Reconnect PCM and CKP sensor harness connectors. Using a voltmeter, measure voltage of 58X reference circuit at PCM harness connector while cranking engine. If reading about 2.5 volts, go tostep 10). If reading is not as specified, go to next step.
9. Inspect connections at CKP sensor. Repair connections as necessary. If connections are okay, replace CKP sensor. Retest system.
10. Inspect connections at PCM. Repair connections as necessary. If connections are okay, replace PCM. Retest system.

An intermittent may be caused by a poor connection, rubbed through wire insulation or a broken wire inside insulation. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. Disconnect PCM connector. Connect voltmeter to CMP signal circuit and wiggle harness and connectors. A change in voltage will indicate area of problem. If DTC cannot be duplicated, check scan tool FAILURE RECORDS to determine mileage since last DTC was set.

1. Perform On-Board Diagnostic (OBD) System Check. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
2. Turn ignition on. Using scan tool, read and record FAIL RECORDS data for DTC P0341. Operate vehicle within FAILURE RECORDS conditions. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0341 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0341 FAILED THIS IGN, check for an intermittent problem, see «DIAGNOSTIC AIDS»(ref-16268-S08387364742001010800000) .
3. Disconnect CMP sensor. Using a voltmeter, measure voltage between sensor ground circuit and senor voltage reference circuit at CMP sensor harness connector. If reading is 4-6 volts, go to next step. If reading is not as specified, go to step 5).
4. Measure voltage between CMP sensor signal circuit and sensor ground circuit at CMP sensor harness connector. If reading is 4-6 volts, go to step 11). If reading is not as specified, go to step 8).
5. If voltage measured in step 3) was less than 4-6 volts, go to next step. If voltage in step 3) was greater than 4-6 volts, repair short to power in CMP sensor voltage reference circuit. Retest system.
6. Inspect CMP sensor for poor connections. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
7. Turn ignition off. Disconnect PCM and CMP sensor harness connectors. Inspect sensor voltage reference circuits for an open between ignition control module and CMP sensor. If a problem is found, repair as necessary. Retest system. If no problem is found, go to step 9).
8. Turn ignition off. Disconnect PCM harness connectors and leave CMP sensor disconnected. Turn ignition on. Using a DVOM, check CMP sensor signal circuit for an open or short to power. Check CMP sensor input circuit for a short to ground. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
9. Check for an open or short in CMP sensor ground circuit. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
10. Check for poor connection at PCM. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
11. Reconnect PCM and CMP sensor harness connectors. Using a voltmeter, backprobe sensor connector at CMP signal circuit. Crank engine and monitor voltage. If voltage toggles between zero and 4 volts, replace PCM. Retest system. If voltage is not as specified, leave voltmeter connected and go to next step.
12. Leaving sensor wiring harness connected, remove CMP sensor. Place a magnet on CMP senor large enough to cover face of sensor. Observe voltmeter. If reading is about zero volts, replace faulty or missing sensor magnet. If reading is not as specified, replace CMP sensor. Retest system.

An intermittent may be caused by a poor connection, rubbed through wire insulation or a broken wire inside insulation. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. Disconnect PCM connector. Connect voltmeter to CMP signal circuit and wiggle harness and connectors. A change in voltage will indicate area of problem. If DTC cannot be duplicated, check scan tool FAILURE RECORDS to determine mileage since last DTC was set.

1. Perform On-Board Diagnostic (OBD) System Check. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
2. Turn ignition on. Using scan tool, read and record FAIL RECORDS data for DTC P0342. Operate vehicle within FAILURE RECORDS conditions. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P0342 FAILED THIS IGN, go to next step. If scan tool does not display DTC P0342 FAILED THIS IGN, check for an intermittent problem, see «DIAGNOSTIC AIDS»(ref-16268-S11624849072001010800000) .
3. Disconnect CMP sensor. Turn ignition on. Using a voltmeter, measure voltage at CMP sensor harness connector between sensor voltage reference circuit and sensor ground circuit. If reading is 4-6 volts, go to step 7). If reading is not as specified, go to next.
4. Turn ignition off. Disconnect PCM and CMP sensor harness connectors. Check for poor connections at CMP sensor. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
5. Check for poor connection at PCM. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
6. Inspect CMP sensor voltage reference circuit for an open or short to ground. Inspect CMP sensor ground circuit for an open or short to power. Repair as necessary. Retest system.
7. With ignition on and engine off, measure voltage between CMP sensor signal circuit and sensor ground circuit at CMP sensor harness connector. If reading is about 4-6 volts, got to next step. If reading is not as specified, go to step 9).
8. Turn ignition off. Disconnect PCM harness connectors. Turn ignition on. Connect a voltmeter between ground and CMP sensor signal circuit at PCM harness connector. Monitor voltage while repeatedly touching CMP sensor signal circuit at CMP sensor connection with a test light to ground. If voltmeter displays voltage toggling between zero and 5 volts when test light is touched to CMP sensor signal circuit, leave voltmeter connected and go to step 12). If voltage is not as specified, go to next step.
9. Leaving PCM disconnected, turn ignition on. Probe CMP sensor signal circuit at PCM harness connector with a test light connected to battery positive terminal. If test light comes on, locate and repair short at ground in CMP signal circuit. Retest system. If test light does not come on, go to next step.
10. Probe CMP sensor signal circuit with a test light connected to ground. If test light comes on, locate and repair short to voltage in CMP sensor signal circuit. Retest system. If test light does not come on, go to next step.
11. Turn ignition off. Disconnect CMP sensor harness connector. Using an ohmmeter, check CMP sensor signal circuit for an open. If problem is found, repair as necessary. Retest system.
12. Remove CMP sensor and reconnect harness connector. Place a magnet on CMP senor large enough to cover face of sensor. Observe voltmeter. If reading is about zero volts, go to next step. If reading is not as specified, replace CMP sensor. Retest system.
13. Reinstall CMP sensor, leaving voltmeter connected. Crank engine and observe voltmeter. If reading toggles between zero and 4 volts, replace PCM. If reading is not as specified, replace faulty or missing CMP sensor magnet. Retest system.

An intermittent may be caused by a poor connection, rubbed through wire insulation or a broken wire inside insulation. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. Using scan tool, monitor DTC P0351-P0356 and wiggle harness and connectors. A change in voltage will indicate area of problem. If DTC cannot be duplicated, check scan tool FAILURE RECORDS to determine mileage since last DTC was set.

1. Perform On-Board Diagnostic (OBD) System Check. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
2. Turn ignition on. Using scan tool, read and record FAIL RECORDS data for DTCs P0351-P0356. Operate vehicle within FAILURE RECORDS conditions. Using scan tool, read SPECIFIC DTC. If scan tool displays a DTC between DTC P0351 and DTC P0356, go to next step. If scan tool does not display any DTC, check for an intermittent problem, see «DIAGNOSTIC AIDS»(ref-16268-S35100452452001010800000) .
3. Check ignition control module for poor connection or damaged terminals. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
4. Check PCM harness connector for poor connection or damaged terminals. If a problem is found, repair as necessary. Retest system. If no problem is found, go to next step.
5. Turn ignition on. Using a voltmeter, backprobe between ground and affected ignition control circuit at PCM harness connector. If reading is 25-55 mV, go to next step. If reading is not as specified, go to step 8).
6. Start engine and let idle. Using voltmeter, backprobe between ground and ignition control circuit at PCM harness connector for cylinder being tested. If reading toggles between 100 and 180 mV, go to next step. If reading is not as specified, replace PCM. Retest system.
7. Turn ignition off. Disconnect 3-pin and 5-pin connectors at ignition control module. Using a voltmeter, measure voltage of affected ignition control circuit at ignition control module while cranking engine. If reading is 200-1200 mV, replace ignition control module. If reading is not as specified, repair open in affected ignition control circuit. Retest system.
8. Turn ignition off. Disconnect PCM and ignition control module harness connectors. Using an ohmmeter, check affected ignition control circuit for a short to ground. Repair as necessary. If circuit is okay, go to next step.
9. Turn ignition on. Using a voltmeter, check affected ignition control circuit for a short to voltage. Repair as necessary. If circuit is okay, replace PCM. Retest system.

An intermittent may be caused by a poor connection, rubbed through wire insulation or a broken wire inside insulation. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. Using scan tool, monitor ACTUAL EGR POSITION and wiggle harness and connectors. A change in voltage will indicate area of problem. If DTC cannot be duplicated, check scan tool FAILURE RECORDS to determine mileage since last DTC was set.

1. Perform On-Board Diagnostic (OBD) System Check. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
2. If DTC P1406 is also set, go to DTC P1406. If DTC P1406 is not set, go to next step.
3. Start engine. Using scan tool, monitor MAP signal. Quickly press throttle half way down and release. If scan tool value made an immediate large change, replace MAP sensor. If scan tool value is not as specified, go to next step.
4. Inspect exhaust system for modifications or leaks. If a problem is found, repair as necessary and go to step 7). If no problem is found, go to next step.
5. Remove EGR valve and check pintle, valve and passages and adapter for excessive deposits or restriction. Check EGR valve gasket and pipes for leaks. If a problem is found, repair as necessary and go to step 7). If no problem is found, go to next step.
6. Remove EGR inlet and outlet pipes from exhaust and intake manifolds. Inspect manifold EGR ports and pipes for blockage. If a problem is found, repair as necessary and go to next step. If no problem is found, check for an intermittent problem, see «DIAGNOSTIC AIDS»(ref-16268-S31866995182001010800000) .
7. Read and record FAIL RECORDS data for DTC P0401. Clear DTCs. Start engine and monitor system info screen while moving connectors and wiring harnesses related to EGR valve. If scan tool displays DTC P0401 FAILED THIS IGN, go to last step completed in this DTC test. If scan tool does not display DTC P0401 FAILED THIS IGN, repair is complete.

An intermittent may be caused by a poor connection, rubbed through wire insulation or a broken wire inside insulation. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. If DTC cannot be duplicated, check scan tool FAILURE RECORDS to determine mileage since last DTC was set.

1. Perform On-Board Diagnostic (OBD) System Check. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
2. Diagnose any other DTCs before proceeding. If no other DTCs are set, go to next step.
3. Ensure TWC is an original equipment part. Check TWC for dents or discoloration caused by excessive heat. Ensure rattle caused by internal catalyst damage does not exist. If a problem is found, repair as necessary and go to step 6). If no problems are found, go to next step.
4. Check exhaust system for leaks, damage, loose or missing hardware. If a problem is found, repair as necessary and go to step 7). If no problems are found, go to next step.
5. Ensure HO2S No. 2, bank 2 is securely installed and that harness is not damaged or contacting exhaust system. If a problem is found, repair as necessary and go to step 7). If no problems are found, go to next step.
6. Replace affected TWC. Check for possible engine misfire DTC or engine mechanical problem, and go to next step.
7. Read and record FAIL RECORDS data for DTC P0420 or DTC P0430. Clear DTCs. Start engine and allow coolant temperature to reach 140°F (60°C). Run engine while monitoring scan tool IAC RPM control function to maintain MAF sensor range at 8-50 grams per second for at least 2 minutes. Go to next step.
8. Using scan tool, monitor TWC MONITOR TEST COUNTER while operating vehicle within conditions required to set DTC. Continue operating vehicle until TWC MONITOR TEST COUNTER reaches 49 and returns to zero at least 2 times. Read SPECIFIC DTC. If scan tool displays DTC P0420 or DTC P0430 TEST RAN AND PASSED, repair is complete. If scan tool does not display DTC P0420 or DTC P0430 TEST RAN AND PASSED, return to step 2).

An intermittent may be caused by a poor connection, rubbed through wire insulation or a broken wire inside insulation. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. If DTC cannot be duplicated, check scan tool FAILURE RECORDS to determine mileage since last DTC was set.

1. Perform On-Board Diagnostic (OBD) System Check. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
2. Diagnose any other DTCs before proceeding. If no other DTCs are set, go to next step.
3. Ensure TWC is an original equipment part. Check TWC for dents or discoloration caused by excessive heat. Ensure rattle caused by internal catalyst damage does not exist. If a problem is found, repair as necessary and go to step 6). If no problems are found, go to next step.
4. Check exhaust system for leaks, damage, loose or missing hardware. If a problem is found, repair as necessary and go to step 7). If no problems are found, go to next step.
5. Ensure HO2S No. 3, bank 1 is securely installed and that harness is not damaged or contacting exhaust system. If a problem is found, repair as necessary and go to step 7). If no problems are found, go to next step.
6. Replace affected TWC. Check for possible engine misfire DTC or engine mechanical problem, and go to next step.
7. Read and record FAIL RECORDS data for DTC P0420 or DTC P0430. Clear DTCs. Start engine and allow coolant temperature to reach 140°F (60°C). Run engine while monitoring scan tool IAC RPM control function to maintain MAF sensor range at 8-50 grams per second for at least 2 minutes. Go to next step.
8. Using scan tool, monitor TWC MONITOR TEST COUNTER while operating vehicle within conditions required to set DTC. Continue operating vehicle until TWC MONITOR TEST COUNTER reaches 49 and returns to zero at least 2 times. Read SPECIFIC DTC. If scan tool displays DTC P0420 or DTC P0430 TEST RAN AND PASSED, repair is complete. If scan tool does not display DTC P0420 or DTC P0430 TEST RAN AND PASSED, return to step 2).

An intermittent may be caused by a cracked or punctured EVAP canister, damaged or disconnected vacuum, vent or purge line. Check for poor connection, rubbed through wire insulation or a broken wire inside insulation. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. If DTC cannot be duplicated, check scan tool FAILURE RECORDS to determine mileage since last DTC was set.

1. Perform On-Board Diagnostic (OBD) System Check. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
2. If DTC P1655 or P1675 is set, diagnose affected DTCs before proceeding. If DTCs are not set, go to next step.
3. Turn ignition off. Remove fuel cap. Turn ignition on. Using scan tool, read FUEL TANK PRESSURE. If scan tool displays zero in. H2O, go to next step. If scan tool does not display zero in. H2O, repair faulty fuel tank pressure sensor circuit.
4. Zero pressure and vacuum gauges on EVAP Pressure/Purge Cart (J41413). Reinstall fuel cap. Read and record FAIL RECORDS data for DTC P0440. Clear DTCs. Using scan tool, command EVAP vent solenoid ON (closed). Connect EVAP pressure/purge cart to EVAP service port. Using EVAP pressure/purge cart, attempt to pressurize EVAP system to 5 in. H2O. If specified pressure is not achieved, to step 6). If specified pressure is achieved, go to next step.
5. Maintain EVAP system pressure at 5 in. H2O. Using scan tool, read FUEL TANK PRESSURE. If scan tool displays -5 in. H2O, go to step 8). If scan tool does not display -5 in. H2O, go to step 7).
6. Disconnect fuel tank vapor and EVAP purge lines from EVAP canister. Plug fuel tank vapor line fitting at EVAP canister. Connect a hand vacuum pump to EVAP purge line fitting at EVAP canister. Ensure EVAP vent solenoid is still commanded ON (closed). Attempt to apply 5 in. Hg vacuum to EVAP canister. If vacuum is maintained as specified, go to step 11). If vacuum can not be maintained as specified, go to step 10).
7. Check fuel tank vapor line and EVAP purge line for restriction. If restriction is found, repair as necessary and go to step 16). If no restriction is found, repair faulty fuel tank pressure sensor circuit.
8. Disconnect vacuum source line and plug vacuum source fitting at EVAP purge solenoid. Using scan tool, select and activate SYSTEM PERF. Using EVAP pressure/purge cart, pressurize EVAP system to 5 in. H2O. Observe pressure gauge on EVAP pressure/purge cart while removing plug from vacuum source fitting line at EVAP purge solenoid. If fuel tank vacuum decreases to zero in. H2O within 15 seconds, go to step 9). If vacuum does not decrease as specified, go to step 13).
9. Connect EVAP pressure/purge cart vacuum gauge to vacuum source line. Start engine. Run engine speed to greater than 2000 RPM while observing vacuum gauge. If vacuum is greater than 15 in. Hg, check for an intermittent problem, see «DIAGNOSTIC AIDS»(ref-16268-S05398302532001010800000) . If vacuum is 15 in. Hg or less, go to step 14).
10. Check if vent hose is disconnected or damaged. Check EVAP canister for damage. If a problem is found, repair as necessary and go to step 16). If no problem is found, go to step 15).
11. Check for missing or faulty fuel cap. Check for disconnected or leaking fuel tank vapor line. Check for disconnected or damaged EVAP purge line. If a problem is found, repair as necessary and go to step 16). If no problem is found, go to next step.
12. Using scan tool, command EVAP vent solenoid ON (closed). With EVAP pressure/purge cart connected to EVAP service port, continuously attempt to pressurize EVAP system by leaving EVAP pressure/purge cart control knob in PRESSURIZE position. Using Ultrasonic Leak Detector (J41416), locate and repair EVAP system leak. It may be necessary to lower fuel tank to check connections at top of tank. Go to step 16).
13. Replace EVAP purge solenoid and go to step 16).
14. Locate and repair cause of no source vacuum to EVAP purge solenoid and go to step 16).
15. Replace EVAP vent solenoid and go to next step.
16. Turn ignition on, engine off. Using scan tool, command EVAP vent solenoid ON (closed). Using EVAP pressure/purge cart pressurize EVAP system to 15 in. H2O. Monitor EVAP pressure/purge cart pressure gauge. Turn EVAP pressure/purge cart rotary switch to HOLD position. If pressure decreases to less than 10 in H2O within 2 minutes, return to step 3). If pressure does not decrease as specified, repair is complete.

An intermittent may be caused by a cracked or punctured EVAP canister, damaged or disconnected vacuum, vent or purge line. Check for poor connection, rubbed through wire insulation or a broken wire inside insulation. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. If DTC cannot be duplicated, check scan tool FAILURE RECORDS to determine mileage since last DTC was set.

1. Perform On-Board Diagnostic (OBD) System Check. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
2. If DTC P1655 or P1675 is set, diagnose affected DTC(s) before proceeding. If DTCs are not set, go to next step.
3. Turn ignition off. Remove fuel cap. Turn ignition on. Using scan tool, read FUEL TANK PRESSURE. If scan tool displays zero in. H2O go to next step. If scan tool does not display zero in. H2O, repair faulty fuel tank pressure sensor circuit.
4. Zero pressure and vacuum gauges on EVAP Pressure/Purge Cart (J41413). Reinstall fuel cap. Read and record FAIL RECORDS data for DTC P0442. Clear DTCs. Connect EVAP pressure/purge cart to EVAP service port. Using scan tool, command EVAP vent solenoid ON (closed). Using EVAP pressure/purge cart, pressurize EVAP system to 5 in. H2O. If specified pressure is achieved, go to next step. If specified pressure is not achieved, repair faulty fuel tank pressure sensor circuit.
5. Start engine and allow to idle. Using scan tool, command EVAP vent solenoid ON (closed). Using EVAP pressure/purge cart pressurize EVAP system to 15 in. H2O. Monitor EVAP pressure/purge cart pressure gauge. Turn EVAP pressure/purge cart rotary switch to HOLD position. If pressure decreases to less than 10 in. H2O within 2 minutes, go to next step. If pressure does not decrease as specified, check for an intermittent problem, see «DIAGNOSTIC AIDS»(ref-16268-S30251544272001010800000) .
6. Disconnect fuel tank vapor and EVAP purge lines from EVAP canister. Plug fuel tank vapor line fitting at EVAP canister. Connect a hand vacuum pump to EVAP purge line fitting at EVAP canister. Ensure EVAP vent solenoid is still commanded ON (closed). Attempt to apply 5 in. Hg vacuum to EVAP canister. If vacuum is maintained as specified, go to step 9). If vacuum can not be maintained as specified, go to next step.
7. Check if vent hose is disconnected or damaged. Check EVAP canister for damage. If a problem is found, repair as necessary and go to step 11). If no problem is found, go to next step.
8. Replace EVAP vent solenoid and go to step 11).
9. Check for missing or faulty fuel cap. Check for disconnected or leaking fuel tank vapor line. Check for disconnected or damaged EVAP purge line. If a problem is found, repair as necessary and go to step 11. If no problem is found, go to next step.
10. Using scan tool, command EVAP vent solenoid on (closed). With EVAP pressure/purge cart connected to EVAP service port, attempt to pressurize EVAP system by leaving EVAP pressure/purge cart control knob in PRESSURIZE position. Using Ultrasonic Leak Detector (J41416), locate and repair EVAP system leak. It may be necessary to lower fuel tank to check connections at top of tank. Go to next step.
11. Turn ignition on, engine off. Using scan tool, command EVAP vent solenoid on (closed). Using EVAP pressure/purge cart pressurize EVAP system to 15 in. H2O. Monitor EVAP pressure/purge cart pressure gauge. Turn EVAP pressure/purge cart rotary switch to HOLD position. If pressure decreases to less than 10 in. H2O within 2 minutes, return to step 3). If pressure does not decrease as specified, repair is complete.

An intermittent may be caused by a damaged, restricted or disconnected vacuum, vent or purge line. Check for poor connection, rubbed through wire insulation or a broken wire inside insulation. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. If DTC cannot be duplicated, check scan tool FAILURE RECORDS to determine mileage since last DTC was set.

1. Perform On-Board Diagnostic (OBD) System Check. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
2. If DTC P1675 is also set, diagnose DTC P1675 before proceeding. If DTC is not set, go to next step.
3. Turn ignition on. Read and record FAIL RECORDS data for DTC P0446. Clear DTCs. Turn ignition off. Remove fuel cap. Turn ignition on. Using scan tool, read FUEL TANK PRESSURE. If scan tool displays zero in. H20, go to next step. If scan tool does not display zero in. H2O, repair faulty fuel tank sensor circuit.
4. Zero pressure and vacuum gauges on EVAP Pressure/Purge Cart (J41413). Reinstall fuel cap. Using scan tool, command EVAP vent solenoid ON (closed). Connect EVAP pressure/purge cart to EVAP service port. Using EVAP pressure/purge cart, pressurize EVAP system to 5 in. H2O. Using scan tool, read FUEL TANK PRESSURE. If scan tool displays 5 in. H2O, go to next step. If scan tool does not display 5 in. H2O, repair faulty fuel tank pressure sensor circuit.
5. Maintain EVAP system pressure at 5 in. H2O. Using scan tool, command EVAP vent solenoid OFF (open). Monitor EVAP pressure/purge cart pressure gauge. If pressure decreases to zero in. H2O within 5 seconds, check for an intermittent problem, see «DIAGNOSTIC AIDS»(ref-16268-S03077819402001010800000) . If pressure does not decrease as specified, go to next step.
6. Disconnect vent hose, marked "AIR", from EVAP canister. Switch EVAP pressure/purge cart rotary switch to PURGE. Start engine and allow it to reach operating temperature. Monitor vacuum gauge for 5 seconds while holding engine speed at 2500 RPM. If vacuum remains at less than 30 in. H2O, go to next step. If vacuum does not remain as specified, go to step 9).
7. Check if vent hose is between EVAP canister and EVAP solenoid is kinked, pinched or blocked. If a problem is found, repair as necessary and go to step 10). If no problem is found, go to next step.
8. Replace EVAP vent solenoid and go to step 10).
9. Replace EVAP canister and go to next step.
10. Using scan tool, command EVAP vent solenoid ON (closed). With EVAP pressure/purge cart connected to EVAP service port, pressurize EVAP system to 5 in. H2O. Switch EVAP pressure/purge cart rotary switch to HOLD. Using scan tool, command EVAP vent solenoid OFF (open). If pressure decreases to zero in. H2O within 5 seconds, repair is complete. If pressure does not decrease as specified, return to step 3).

Check for poor connection, rubbed through wire insulation or a broken wire inside insulation. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. Using scan tool monitor fuel level display while moving connectors and harness related to fuel sensor. Change in display will indicate problem area.

1. Perform On-Board Diagnostic (OBD) System Check. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
2. If a Vehicle Speed Sensor (VSS) DTC is also set, diagnose it before proceeding. If a VSS DTC is not set, go to next step.
3. Remove fuel level sensor from fuel tank. Ensure sensor arm moves freely. If sensor arm does not move freely, replace fuel level sensor. Retest system. If fuel level sensor is okay, go to next step.
4. Connect an analog ohmmeter to fuel level sensor. As arm of sensor is moved, needle on meter should move smoothly. Replace fuel level sensor if operation is not as specified. Retest system. If operation is as specified, go to next step.
5. Using an ohmmeter, measure resistance of fuel level sensor as arm is moved from empty to full positions. Ensure resistance is within specification. See «FUEL LEVEL SENSOR SPECIFICATIONS»(ref-16268-S29705440292001010800000) . Replace fuel level sensor if operation is not as specified. If fuel level sensor tests okay, replace PCM. Retest system. FUEL LEVEL SENSOR SPECIFICATIONS Position Ohms "E" 102.5-120.5 1/6 73 1/3 56 1/2 45 2/3 36.75 5/6 30 "F" 17-23.5

Check for poor connection, rubbed through wire insulation or a broken wire inside insulation. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. Using scan tool monitor fuel level display while moving connectors and harness related to fuel sensor. Change in display will indicate problem area.

1. Perform On-Board Diagnostic (OBD) System Check. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
2. If any Engine Coolant Temperature (ECT) or Manifold Absolute Pressure (MAP) sensor DTCs are set, diagnose them first. If no other DTCs are set, go to next step.
3. Disconnect fuel level sensor harness connector. Turn ignition on. Using a voltmeter, measure voltage between sensor harness positive and ground wires. If reading is 5 volts, go to step 8). If reading is not as specified, go to next step.
4. Using a voltmeter, backprobe between ground and PCM harness connector terminal which supplies 5 volts to fuel level sensor. If reading is 5 volts, go to next step. If reading is not as specified, replace PCM. Retest system.
5. Backprobe between ground and 5-volt reference circuit at sensor. If reading is about same as in step 4), go to step 7). If reading is not as specified, go to next step.
6. Check for an open or high resistance in 5-volt reference circuit between PCM and fuel level sensor. Repair as necessary. Retest system.
7. Check for an open or high resistance in ground circuit between PCM and fuel level sensor. Repair as necessary. Retest system.
8. Remove fuel level sensor from fuel tank. Ensure sensor arm moves freely. Using an ohmmeter, measure resistance of fuel level sensor as arm is moved from empty to full positions. Ensure resistance is within specification. See «FUEL LEVEL SENSOR SPECIFICATIONS»(ref-16268-S29705440292001010800000) . Replace fuel level sensor if operation is not as specified. If fuel level sensor tests okay, replace PCM. Retest system.

Check for poor connection, rubbed through wire insulation or a broken wire inside insulation. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. Using scan tool monitor fuel level display while moving connectors and harness related to fuel sensor. Change in display will indicate problem area.

1. Perform On-Board Diagnostic (OBD) System Check. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
2. If any Engine Coolant Temperature (ECT) or Manifold Absolute Pressure (MAP) sensor DTCs are set, diagnose them first. If no other DTCs are set, go to next step.
3. Disconnect fuel level sensor harness connector. Turn ignition on. Using a voltmeter, measure voltage between sensor harness positive and ground wires. If reading is 5 volts, go to step 8). If reading is not as specified, go to next step.
4. Turn ignition off. Reconnect fuel level sensor harness connector. Turn ignition on. Using a voltmeter, connect negative lead to ground. Backprobe positive lead to sensor ground circuit at harness connector. If voltmeter indicates a short to voltage source, go to next step. If no short is detected, go to step 6).
5. Repair short to voltage between fuel level sensor and PCM. Retest system.
6. With negative lead still connected to ground, backprobe 5-volt reference sensor circuit at harness connector. If reading is greater than 5 volts, repair circuit for short to power. If reading is not as specified, go to next step.
7. Check 5-volt reference circuit for short to ground. Repair as necessary. If no short is found, replace PCM. Retest system.
8. Turn ignition off. Remove fuel level sensor from fuel tank. Ensure sensor arm moves freely. Using an ohmmeter, measure resistance of fuel level sensor as arm is moved from empty to full positions. Ensure resistance is within specification. See «FUEL LEVEL SENSOR SPECIFICATIONS»(ref-16268-S29705440292001010800000) . Replace fuel level sensor if operation is not as specified. If fuel level sensor tests okay, replace PCM. Retest system.